1
|
Shah DD, Carter P, Shivdasani MN, Fong N, Duan W, Esrafilzadeh D, Poole-Warren LA, Aregueta Robles UA. Deciphering platinum dissolution in neural stimulation electrodes: Electrochemistry or biology? Biomaterials 2024; 309:122575. [PMID: 38677220 DOI: 10.1016/j.biomaterials.2024.122575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/28/2024] [Accepted: 04/13/2024] [Indexed: 04/29/2024]
Abstract
Platinum (Pt) is the metal of choice for electrodes in implantable neural prostheses like the cochlear implants, deep brain stimulating devices, and brain-computer interfacing technologies. However, it is well known since the 1970s that Pt dissolution occurs with electrical stimulation. More recent clinical and in vivo studies have shown signs of corrosion in explanted electrode arrays and the presence of Pt-containing particulates in tissue samples. The process of degradation and release of metallic ions and particles can significantly impact on device performance. Moreover, the effects of Pt dissolution products on tissue health and function are still largely unknown. This is due to the highly complex chemistry underlying the dissolution process and the difficulty in decoupling electrical and chemical effects on biological responses. Understanding the mechanisms and effects of Pt dissolution proves challenging as the dissolution process can be influenced by electrical, chemical, physical, and biological factors, all of them highly variable between experimental settings. By evaluating comprehensive findings on Pt dissolution mechanisms reported in the fuel cell field, this review presents a critical analysis of the possible mechanisms that drive Pt dissolution in neural stimulation in vitro and in vivo. Stimulation parameters, such as aggregate charge, charge density, and electrochemical potential can all impact the levels of dissolved Pt. However, chemical factors such as electrolyte types, dissolved gases, and pH can all influence dissolution, confounding the findings of in vitro studies with multiple variables. Biological factors, such as proteins, have been documented to exhibit a mitigating effect on the dissolution process. Other biological factors like cells and fibro-proliferative responses, such as fibrosis and gliosis, impact on electrode properties and are suspected to impact on Pt dissolution. However, the relationship between electrical properties of stimulating electrodes and Pt dissolution remains contentious. Host responses to Pt degradation products are also controversial due to the unknown chemistry of Pt compounds formed and the lack of understanding of Pt distribution in clinical scenarios. The cytotoxicity of Pt produced via electrical stimulation appears similar to Pt-based compounds, including hexachloroplatinates and chemotherapeutic agents like cisplatin. While the levels of Pt produced under clinical and acute stimulation regimes were typically an order of magnitude lower than toxic concentrations observed in vitro, further research is needed to accurately assess the mass balance and type of Pt produced during long-term stimulation and its impact on tissue response. Finally, approaches to mitigating the dissolution process are reviewed. A wide variety of approaches, including stimulation strategies, coating electrode materials, and surface modification techniques to avoid excess charge during stimulation and minimise tissue response, may ultimately support long-term and safe operation of neural stimulating devices.
Collapse
Affiliation(s)
- Dhyey Devashish Shah
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Paul Carter
- Cochlear Ltd, Macquarie University, NSW, Australia
| | | | - Nicole Fong
- Cochlear Ltd, Macquarie University, NSW, Australia
| | - Wenlu Duan
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Dorna Esrafilzadeh
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia
| | - Laura Anne Poole-Warren
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia; The Tyree Foundation Institute of Health Engineering, University of New South Wales, Sydney, Australia.
| | | |
Collapse
|
2
|
Ferro MD, Proctor CM, Gonzalez A, Jayabal S, Zhao E, Gagnon M, Slézia A, Pas J, Dijk G, Donahue MJ, Williamson A, Raymond J, Malliaras GG, Giocomo L, Melosh NA. NeuroRoots, a bio-inspired, seamless brain machine interface for long-term recording in delicate brain regions. AIP ADVANCES 2024; 14:085109. [PMID: 39130131 PMCID: PMC11309783 DOI: 10.1063/5.0216979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 07/09/2024] [Indexed: 08/13/2024]
Abstract
Scalable electronic brain implants with long-term stability and low biological perturbation are crucial technologies for high-quality brain-machine interfaces that can seamlessly access delicate and hard-to-reach regions of the brain. Here, we created "NeuroRoots," a biomimetic multi-channel implant with similar dimensions (7 μm wide and 1.5 μm thick), mechanical compliance, and spatial distribution as axons in the brain. Unlike planar shank implants, these devices consist of a number of individual electrode "roots," each tendril independent from the other. A simple microscale delivery approach based on commercially available apparatus minimally perturbs existing neural architectures during surgery. NeuroRoots enables high density single unit recording from the cerebellum in vitro and in vivo. NeuroRoots also reliably recorded action potentials in various brain regions for at least 7 weeks during behavioral experiments in freely-moving rats, without adjustment of electrode position. This minimally invasive axon-like implant design is an important step toward improving the integration and stability of brain-machine interfacing.
Collapse
Affiliation(s)
- Marc D. Ferro
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | - Christopher M. Proctor
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Alexander Gonzalez
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California 94304, USA
| | - Sriram Jayabal
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California 94304, USA
| | - Eric Zhao
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | - Maxwell Gagnon
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California 94304, USA
| | - Andrea Slézia
- Multimodal Neurotechnology Group, Institute of Cognitive Neuroscience and Psychology, HUN-REN Research Centre for Natural Sciences, Hungarian Research Network, 1117 Budapest, Magyar tudósok körútja 2., Hungary
| | - Jolien Pas
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, 13541 Gardanne, France
| | - Gerwin Dijk
- Department of Bioelectronics, Ecole Nationale Supérieure des Mines, CMP-EMSE, 13541 Gardanne, France
| | - Mary J. Donahue
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, Norrköping, 60221, Sweden
| | | | - Jennifer Raymond
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California 94304, USA
| | - George G. Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Lisa Giocomo
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California 94304, USA
| | - Nicholas A. Melosh
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| |
Collapse
|
3
|
Berger E, Brandes G, Kaiser O, Reifenrath J, Lenarz T, Wissel K, Durisin M. Induction of cell death by sodium hexachloroplatinate (IV) in the HEI-OC1 cell line, primary rat spiral ganglion cells and rat organ of Corti explants. PLoS One 2024; 19:e0307973. [PMID: 39058727 PMCID: PMC11280268 DOI: 10.1371/journal.pone.0307973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 07/15/2024] [Indexed: 07/28/2024] Open
Abstract
Although cochlear implants have become a well-established method for patients with sensory neural hearing loss, clinical results indicate that in some cases, corrosion of electrode contacts leads to high impedance that interferes with successful stimulation of the auditory nerve. As it is unclear whether corrosion products induce cell damage, we focused on cell culture models of the organ of Corti cell line (HEI-OC1), rat spiral ganglion cells (SGC) and rat organ of Corti explant (OCex) cultivated from neonatal rat cochleae to characterize the cytotoxicity of sodium hexachloroplatinate (IV) (Na2(PtCl6)). The oxidative activity in HEI-OC1 cells decreased with increasing Na2(PtCl6) concentrations between 8 and 16 ng/μl, and live cell staining with Calcein acetoxymethyl/Ethidium homodimer III revealed an increasing number of cells with disrupted membranes. Ultrastructural evidence of mitophagy followed by necroptosis was detected. Additionally, exposure of the SGC to 15-35 ng/μl Na2(PtCl6) dose-dependently reduced neuronal survival and neuritogenesis, as determined by neurofilament antigen staining. In parallel, staining glial cells and fibroblasts with specific antibodies confirmed the dose-dependent induction of cell death by Na2(PtCl6). Exposure of the OCex to 25-45 ng/μl Na2(PtCl6) resulted in severe concentration-dependent hair cell loss. Our data show for the first time that Na2(PtCl6) induces cell death in a concentration-dependent manner in inner ear cell types and tissues.
Collapse
Affiliation(s)
- Elisabeth Berger
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany
| | - Gudrun Brandes
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, Hannover, Germany
| | - Odett Kaiser
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany
| | - Janin Reifenrath
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany
- Clinic for Orthopaedic Surgery, Hannover Medical School, Hannover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany
| | - Kirsten Wissel
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany
| | - Martin Durisin
- Department of Otorhinolaryngology, Hannover Medical School, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover Medical School, Hannover, Germany
- University Clinic of Otolaryngology, Head and Neck Surgery, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| |
Collapse
|
4
|
Rezayat L, Ghajar MH, Naji A, Noroozi J, Dehaqani MRA, Rezayat E. A low-cost protocol for reconditioning of deep-brain neural microelectrodes with material failure for electrophysiology recording. Biomed Phys Eng Express 2024; 10:055014. [PMID: 39013391 DOI: 10.1088/2057-1976/ad63ad] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 07/16/2024] [Indexed: 07/18/2024]
Abstract
To date, a myriad of neural microelectrodes has been meticulously developed, but the focus of existing literature predominantly revolves around fabrication methodologies rather than delving into the reconditioning processes or strategies for salvaging electrodes exhibiting diminished performance due to material failure. This study aims to elucidate the underlying factors contributing to the degradation in performance of neural microelectrodes. Additionally, it introduces a comprehensive, cost-effective protocol for the reconditioning and repurposing of electrodes afflicted by material failure, tailored for a broad spectrum of electrode types. The efficacy of the proposed reconditioning protocol is substantiated through experimental validation on single-site tungsten microelectrodes. The results of neural signal recording unequivocally demonstrate the successful restoration of a substantial number of electrodes, underscoring the protocol's effectiveness.
Collapse
Affiliation(s)
- Leila Rezayat
- Research Laboratory for Integrated Circuits & Systems (ICAS), K.N. Toosi University of Technology, Tehran, Iran
- Department of Cognitive Sciences, Faculty of Psychology and Education, University of Tehran, Tehran, Iran
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Niavaran, Tehran, Iran
| | - Mohammad Hossein Ghajar
- Department of Neurosurgery, University of Texas Health Science Center, Houston, TX, 77030, United States of America
| | - Alireza Naji
- Department of Electrical Engineering, Faculty of Engineering, University of Guilan, Rasht, Iran
| | - Jalaledin Noroozi
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Niavaran, Tehran, Iran
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohammad-Reza A Dehaqani
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Niavaran, Tehran, Iran
- School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Ehsan Rezayat
- Department of Cognitive Sciences, Faculty of Psychology and Education, University of Tehran, Tehran, Iran
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Niavaran, Tehran, Iran
| |
Collapse
|
5
|
Abbott JR, Jeakle EN, Haghighi P, Usoro JO, Sturgill BS, Wu Y, Geramifard N, Radhakrishna R, Patnaik S, Nakajima S, Hess J, Mehmood Y, Devata V, Vijayakumar G, Sood A, Doan Thai TT, Dogra K, Hernandez-Reynoso AG, Pancrazio JJ, Cogan SF. Planar amorphous silicon carbide microelectrode arrays for chronic recording in rat motor cortex. Biomaterials 2024; 308:122543. [PMID: 38547834 PMCID: PMC11065583 DOI: 10.1016/j.biomaterials.2024.122543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 03/05/2024] [Accepted: 03/19/2024] [Indexed: 04/21/2024]
Abstract
Chronic implantation of intracortical microelectrode arrays (MEAs) capable of recording from individual neurons can be used for the development of brain-machine interfaces. However, these devices show reduced recording capabilities under chronic conditions due, at least in part, to the brain's foreign body response (FBR). This creates a need for MEAs that can minimize the FBR to possibly enable long-term recording. A potential approach to reduce the FBR is the use of MEAs with reduced cross-sectional geometries. Here, we fabricated 4-shank amorphous silicon carbide (a-SiC) MEAs and implanted them into the motor cortex of seven female Sprague-Dawley rats. Each a-SiC MEA shank was 8 μm thick by 20 μm wide and had sixteen sputtered iridium oxide film (SIROF) electrodes (4 per shank). A-SiC was chosen as the fabrication base for its high chemical stability, good electrical insulation properties, and amenability to thin film fabrication. Electrochemical analysis and neural recordings were performed weekly for 4 months. MEAs were characterized pre-implantation in buffered saline and in vivo using electrochemical impedance spectroscopy and cyclic voltammetry at 50 mV/s and 50,000 mV/s. Neural recordings were analyzed for single unit activity. At the end of the study, animals were sacrificed for immunohistochemical analysis. We observed statistically significant, but small, increases in 1 and 30 kHz impedance values and 50,000 mV/s charge storage capacity over the 16-week implantation period. Slow sweep 50 mV/s CV and 1 Hz impedance did not significantly change over time. Impedance values increased from 11.6 MΩ to 13.5 MΩ at 1 Hz, 1.2 MΩ-2.9 MΩ at 1 kHz, and 0.11 MΩ-0.13 MΩ at 30 kHz over 16 weeks. The median charge storage capacity of the implanted electrodes at 50 mV/s was 58.1 mC/cm2 on week 1 and 55.9 mC/cm2 on week 16, and at 50,000 mV/s, 4.27 mC/cm2 on week 1 and 5.93 mC/cm2 on week 16. Devices were able to record neural activity from 92% of all active channels at the beginning of the study, At the study endpoint, a-SiC devices were still recording single-unit activity on 51% of electrochemically active electrode channels. In addition, we observed that the signal-to-noise ratio experienced a small decline of -0.19 per week. We also classified observed units as fast and slow repolarizing based on the trough-to-peak time. Although the overall presence of single units declined, fast and slow repolarizing units declined at a similar rate. At recording electrode depth, immunohistochemistry showed minimal tissue response to the a-SiC devices, as indicated by statistically insignificant differences in activated glial cell response between implanted brains slices and contralateral sham slices at 150 μm away from the implant location, as evidenced by GFAP staining. NeuN staining revealed the presence of neuronal cell bodies close to the implantation site, again statistically not different from a contralateral sham slice. These results warrant further investigation of a-SiC MEAs for future long-term implantation neural recording studies.
Collapse
Affiliation(s)
- Justin R Abbott
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Eleanor N Jeakle
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Pegah Haghighi
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Joshua O Usoro
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Brandon S Sturgill
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Yupeng Wu
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Negar Geramifard
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Rahul Radhakrishna
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Sourav Patnaik
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Shido Nakajima
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Jordan Hess
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX, United States
| | - Yusef Mehmood
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Veda Devata
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, TX, United States
| | - Gayathri Vijayakumar
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX, United States
| | - Armaan Sood
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX, United States
| | - Teresa Thuc Doan Thai
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Komal Dogra
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Ana G Hernandez-Reynoso
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Stuart F Cogan
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States.
| |
Collapse
|
6
|
Duan W, Robles UA, Poole‐Warren L, Esrafilzadeh D. Bioelectronic Neural Interfaces: Improving Neuromodulation Through Organic Conductive Coatings. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2306275. [PMID: 38115740 PMCID: PMC11251570 DOI: 10.1002/advs.202306275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/07/2023] [Indexed: 12/21/2023]
Abstract
Integration of bioelectronic devices in clinical practice is expanding rapidly, focusing on conditions ranging from sensory to neurological and mental health disorders. While platinum (Pt) electrodes in neuromodulation devices such as cochlear implants and deep brain stimulators have shown promising results, challenges still affect their long-term performance. Key among these are electrode and device longevity in vivo, and formation of encapsulating fibrous tissue. To overcome these challenges, organic conductors with unique chemical and physical properties are being explored. They hold great promise as coatings for neural interfaces, offering more rapid regulatory pathways and clinical implementation than standalone bioelectronics. This study provides a comprehensive review of the potential benefits of organic coatings in neuromodulation electrodes and the challenges that limit their effective integration into existing devices. It discusses issues related to metallic electrode use and introduces physical, electrical, and biological properties of organic coatings applied in neuromodulation. Furthermore, previously reported challenges related to organic coating stability, durability, manufacturing, and biocompatibility are thoroughly reviewed and proposed coating adhesion mechanisms are summarized. Understanding organic coating properties, modifications, and current challenges of organic coatings in clinical and industrial settings is expected to provide valuable insights for their future development and integration into organic bioelectronics.
Collapse
Affiliation(s)
- Wenlu Duan
- The Graduate School of Biomedical EngineeringUNSWSydneyNSW2052Australia
| | | | - Laura Poole‐Warren
- The Graduate School of Biomedical EngineeringUNSWSydneyNSW2052Australia
- Tyree Foundation Institute of Health EngineeringUNSWSydneyNSW2052Australia
| | | |
Collapse
|
7
|
Wu Y, Temple BA, Sevilla N, Zhang J, Zhu H, Zolotavin P, Jin Y, Duarte D, Sanders E, Azim E, Nimmerjahn A, Pfaff SL, Luan L, Xie C. Ultraflexible electrodes for recording neural activity in the mouse spinal cord during motor behavior. Cell Rep 2024; 43:114199. [PMID: 38728138 PMCID: PMC11233142 DOI: 10.1016/j.celrep.2024.114199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 03/10/2024] [Accepted: 04/22/2024] [Indexed: 05/12/2024] Open
Abstract
Implantable electrode arrays are powerful tools for directly interrogating neural circuitry in the brain, but implementing this technology in the spinal cord in behaving animals has been challenging due to the spinal cord's significant motion with respect to the vertebral column during behavior. Consequently, the individual and ensemble activity of spinal neurons processing motor commands remains poorly understood. Here, we demonstrate that custom ultraflexible 1-μm-thick polyimide nanoelectronic threads can conduct laminar recordings of many neuronal units within the lumbar spinal cord of unrestrained, freely moving mice. The extracellular action potentials have high signal-to-noise ratio, exhibit well-isolated feature clusters, and reveal diverse patterns of activity during locomotion. Furthermore, chronic recordings demonstrate the stable tracking of single units and their functional tuning over multiple days. This technology provides a path for elucidating how spinal circuits compute motor actions.
Collapse
Affiliation(s)
- Yu Wu
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA; Rice Neuroengineering Initiative, Rice University, Houston, TX 77030, USA
| | - Benjamin A Temple
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA 92037, USA
| | - Nicole Sevilla
- Rice Neuroengineering Initiative, Rice University, Houston, TX 77030, USA; Department of Bioengineering, Rice University, Houston, TX 77030, USA
| | - Jiaao Zhang
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA; Rice Neuroengineering Initiative, Rice University, Houston, TX 77030, USA
| | - Hanlin Zhu
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA; Rice Neuroengineering Initiative, Rice University, Houston, TX 77030, USA
| | - Pavlo Zolotavin
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA; Rice Neuroengineering Initiative, Rice University, Houston, TX 77030, USA
| | - Yifu Jin
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA; Rice Neuroengineering Initiative, Rice University, Houston, TX 77030, USA
| | - Daniela Duarte
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Elischa Sanders
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Eiman Azim
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Axel Nimmerjahn
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Samuel L Pfaff
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| | - Lan Luan
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA; Rice Neuroengineering Initiative, Rice University, Houston, TX 77030, USA; Department of Bioengineering, Rice University, Houston, TX 77030, USA.
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA; Rice Neuroengineering Initiative, Rice University, Houston, TX 77030, USA; Department of Bioengineering, Rice University, Houston, TX 77030, USA.
| |
Collapse
|
8
|
Woodington BJ, Lei J, Carnicer-Lombarte A, Güemes-González A, Naegele TE, Hilton S, El-Hadwe S, Trivedi RA, Malliaras GG, Barone DG. Flexible circumferential bioelectronics to enable 360-degree recording and stimulation of the spinal cord. SCIENCE ADVANCES 2024; 10:eadl1230. [PMID: 38718109 PMCID: PMC11078185 DOI: 10.1126/sciadv.adl1230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 04/04/2024] [Indexed: 05/12/2024]
Abstract
The spinal cord is crucial for transmitting motor and sensory information between the brain and peripheral systems. Spinal cord injuries can lead to severe consequences, including paralysis and autonomic dysfunction. We introduce thin-film, flexible electronics for circumferential interfacing with the spinal cord. This method enables simultaneous recording and stimulation of dorsal, lateral, and ventral tracts with a single device. Our findings include successful motor and sensory signal capture and elicitation in anesthetized rats, a proof-of-concept closed-loop system for bridging complete spinal cord injuries, and device safety verification in freely moving rodents. Moreover, we demonstrate potential for human application through a cadaver model. This method sees a clear route to the clinic by using materials and surgical practices that mitigate risk during implantation and preserve cord integrity.
Collapse
Affiliation(s)
- Ben J. Woodington
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Jiang Lei
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | | | - Amparo Güemes-González
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Tobias E. Naegele
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Sam Hilton
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Salim El-Hadwe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Rikin A. Trivedi
- Division of Neurosurgery, Addenbrookes Hospital, Hills Road, Cambridge, UK
| | - George G. Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Damiano G. Barone
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| |
Collapse
|
9
|
Hamani C, Davidson B, Lipsman N, Abrahao A, Nestor SM, Rabin JS, Giacobbe P, Pagano RL, Campos ACP. Insertional effect following electrode implantation: an underreported but important phenomenon. Brain Commun 2024; 6:fcae093. [PMID: 38707711 PMCID: PMC11069120 DOI: 10.1093/braincomms/fcae093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/08/2023] [Accepted: 03/26/2024] [Indexed: 05/07/2024] Open
Abstract
Deep brain stimulation has revolutionized the treatment of movement disorders and is gaining momentum in the treatment of several other neuropsychiatric disorders. In almost all applications of this therapy, the insertion of electrodes into the target has been shown to induce some degree of clinical improvement prior to stimulation onset. Disregarding this phenomenon, commonly referred to as 'insertional effect', can lead to biased results in clinical trials, as patients receiving sham stimulation may still experience some degree of symptom amelioration. Similar to the clinical scenario, an improvement in behavioural performance following electrode implantation has also been reported in preclinical models. From a neurohistopathologic perspective, the insertion of electrodes into the brain causes an initial trauma and inflammatory response, the activation of astrocytes, a focal release of gliotransmitters, the hyperexcitability of neurons in the vicinity of the implants, as well as neuroplastic and circuitry changes at a distance from the target. Taken together, it would appear that electrode insertion is not an inert process, but rather triggers a cascade of biological processes, and, as such, should be considered alongside the active delivery of stimulation as an active part of the deep brain stimulation therapy.
Collapse
Affiliation(s)
- Clement Hamani
- Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada
| | - Benjamin Davidson
- Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada
| | - Nir Lipsman
- Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada
| | - Agessandro Abrahao
- Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Division of Neurology, Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada
| | - Sean M Nestor
- Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Department of Psychiatry, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada
| | - Jennifer S Rabin
- Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Division of Neurology, Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto M5G 1V7, Canada
| | - Peter Giacobbe
- Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
- Department of Psychiatry, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada
| | - Rosana L Pagano
- Laboratory of Neuroscience, Hospital Sírio-Libanês, São Paulo, SP CEP 01308-060, Brazil
| | - Ana Carolina P Campos
- Sunnybrook Research Institute, Toronto, ON M4N 3M5, Canada
- Laboratory of Neuroscience, Hospital Sírio-Libanês, São Paulo, SP CEP 01308-060, Brazil
| |
Collapse
|
10
|
Sturgill B, Hernandez-Reynoso AG, Druschel LN, Smith TJ, Boucher PE, Hoeferlin GF, Thai TTD, Jiang MS, Hess JL, Alam NN, Menendez DM, Duncan JL, Cogan SF, Pancrazio JJ, Capadona JR. Reactive Amine Functionalized Microelectrode Arrays Provide Short-Term Benefit but Long-Term Detriment to In Vivo Recording Performance. ACS APPLIED BIO MATERIALS 2024; 7:1052-1063. [PMID: 38290529 PMCID: PMC10880090 DOI: 10.1021/acsabm.3c01014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 02/01/2024]
Abstract
Intracortical microelectrode arrays (MEAs) are used for recording neural signals. However, indwelling devices result in chronic neuroinflammation, which leads to decreased recording performance through degradation of the device and surrounding tissue. Coating the MEAs with bioactive molecules is being explored to mitigate neuroinflammation. Such approaches often require an intermediate functionalization step such as (3-aminopropyl)triethoxysilane (APTES), which serves as a linker. However, the standalone effect of this intermediate step has not been previously characterized. Here, we investigated the effect of coating MEAs with APTES by comparing APTES-coated to uncoated controls in vivo and ex vivo. First, we measured water contact angles between silicon uncoated and APTES-coated substrates to verify the hydrophilic characteristics of the APTES coating. Next, we implanted MEAs in the motor cortex (M1) of Sprague-Dawley rats with uncoated or APTES-coated devices. We assessed changes in the electrochemical impedance and neural recording performance over a chronic implantation period of 16 weeks. Additionally, histology and bulk gene expression were analyzed to understand further the reactive tissue changes arising from the coating. Results showed that APTES increased the hydrophilicity of the devices and decreased electrochemical impedance at 1 kHz. APTES coatings proved detrimental to the recording performance, as shown by a constant decay up to 16 weeks postimplantation. Bulk gene analysis showed differential changes in gene expression between groups that were inconclusive with regard to the long-term effect on neuronal tissue. Together, these results suggest that APTES coatings are ultimately detrimental to chronic neural recordings. Furthermore, interpretations of studies using APTES as a functionalization step should consider the potential consequences if the final functionalization step is incomplete.
Collapse
Affiliation(s)
- Brandon
S. Sturgill
- Department
of Bioengineering, The University of Texas
at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Ana G. Hernandez-Reynoso
- Department
of Bioengineering, The University of Texas
at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Lindsey N. Druschel
- Department
of Biomedical Engineering, Case Western
Reserve University. 10900 Euclid Ave, Cleveland, Ohio 44106, United States
- Advanced
Platform Technology Center, Louis Stokes Cleveland Veterans Affairs
Medical Center, Cleveland, Ohio 44106, United States
| | - Thomas J. Smith
- School
of Behavioral and BrainSciences, The University
of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Pierce E. Boucher
- Department
of Biomedical Engineering, Case Western
Reserve University. 10900 Euclid Ave, Cleveland, Ohio 44106, United States
- Advanced
Platform Technology Center, Louis Stokes Cleveland Veterans Affairs
Medical Center, Cleveland, Ohio 44106, United States
| | - George F. Hoeferlin
- Department
of Biomedical Engineering, Case Western
Reserve University. 10900 Euclid Ave, Cleveland, Ohio 44106, United States
- Advanced
Platform Technology Center, Louis Stokes Cleveland Veterans Affairs
Medical Center, Cleveland, Ohio 44106, United States
| | - Teresa Thuc Doan Thai
- Department
of Bioengineering, The University of Texas
at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Madison S. Jiang
- School
of Behavioral and BrainSciences, The University
of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Jordan L. Hess
- School
of Behavioral and BrainSciences, The University
of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Neeha N. Alam
- Department
of Bioengineering, The University of Texas
at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Dhariyat M. Menendez
- Department
of Biomedical Engineering, Case Western
Reserve University. 10900 Euclid Ave, Cleveland, Ohio 44106, United States
- Advanced
Platform Technology Center, Louis Stokes Cleveland Veterans Affairs
Medical Center, Cleveland, Ohio 44106, United States
| | - Jonathan L. Duncan
- Department
of Biomedical Engineering, Case Western
Reserve University. 10900 Euclid Ave, Cleveland, Ohio 44106, United States
- Advanced
Platform Technology Center, Louis Stokes Cleveland Veterans Affairs
Medical Center, Cleveland, Ohio 44106, United States
| | - Stuart F. Cogan
- Department
of Bioengineering, The University of Texas
at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Joseph J. Pancrazio
- Department
of Bioengineering, The University of Texas
at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Jeffrey R. Capadona
- Department
of Biomedical Engineering, Case Western
Reserve University. 10900 Euclid Ave, Cleveland, Ohio 44106, United States
- Advanced
Platform Technology Center, Louis Stokes Cleveland Veterans Affairs
Medical Center, Cleveland, Ohio 44106, United States
| |
Collapse
|
11
|
Hernandez-Reynoso AG, Sturgill BS, Hoeferlin GF, Druschel LN, Krebs OK, Menendez DM, Thai TTD, Smith TJ, Duncan J, Zhang J, Mittal G, Radhakrishna R, Desai MS, Cogan SF, Pancrazio JJ, Capadona JR. The effect of a Mn(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP) coating on the chronic recording performance of planar silicon intracortical microelectrode arrays. Biomaterials 2023; 303:122351. [PMID: 37931456 PMCID: PMC10842897 DOI: 10.1016/j.biomaterials.2023.122351] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/27/2023] [Accepted: 10/11/2023] [Indexed: 11/08/2023]
Abstract
Intracortical microelectrode arrays (MEAs) are used to record neural activity. However, their implantation initiates a neuroinflammatory cascade, involving the accumulation of reactive oxygen species, leading to interface failure. Here, we coated commercially-available MEAs with Mn(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP), to mitigate oxidative stress. First, we assessed the in vitro cytotoxicity of modified sample substrates. Then, we implanted 36 rats with uncoated, MnTBAP-coated ("Coated"), or (3-Aminopropyl)triethoxysilane (APTES)-coated devices - an intermediate step in the coating process. We assessed electrode performance during the acute (1-5 weeks), sub-chronic (6-11 weeks), and chronic (12-16 weeks) phases after implantation. Three subsets of animals were euthanized at different time points to assess the acute, sub-chronic and chronic immunohistological responses. Results showed that MnTBAP coatings were not cytotoxic in vitro, and their implantation in vivo improved the proportion of electrodes during the sub-chronic and chronic phases; APTES coatings resulted in failure of the neural interface during the chronic phase. In addition, MnTBAP coatings improved the quality of the signal throughout the study and reduced the neuroinflammatory response around the implant as early as two weeks, an effect that remained consistent for months post-implantation. Together, these results suggest that MnTBAP coatings are a potentially useful modification to improve MEA reliability.
Collapse
Affiliation(s)
- Ana G Hernandez-Reynoso
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Brandon S Sturgill
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - George F Hoeferlin
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Lindsey N Druschel
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Olivia K Krebs
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Dhariyat M Menendez
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Teresa T D Thai
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Thomas J Smith
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Jonathan Duncan
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Jichu Zhang
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Gaurav Mittal
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| | - Rahul Radhakrishna
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Mrudang Spandan Desai
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Stuart F Cogan
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, United States.
| | - Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH, 44106, United States.
| |
Collapse
|
12
|
Kirchherr S, Mildiner Moraga S, Coudé G, Bimbi M, Ferrari PF, Aarts E, Bonaiuto JJ. Bayesian multilevel hidden Markov models identify stable state dynamics in longitudinal recordings from macaque primary motor cortex. Eur J Neurosci 2023; 58:2787-2806. [PMID: 37382060 DOI: 10.1111/ejn.16065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 04/02/2023] [Accepted: 06/01/2023] [Indexed: 06/30/2023]
Abstract
Neural populations, rather than single neurons, may be the fundamental unit of cortical computation. Analysing chronically recorded neural population activity is challenging not only because of the high dimensionality of activity but also because of changes in the signal that may or may not be due to neural plasticity. Hidden Markov models (HMMs) are a promising technique for analysing such data in terms of discrete latent states, but previous approaches have not considered the statistical properties of neural spiking data, have not been adaptable to longitudinal data, or have not modelled condition-specific differences. We present a multilevel Bayesian HMM addresses these shortcomings by incorporating multivariate Poisson log-normal emission probability distributions, multilevel parameter estimation and trial-specific condition covariates. We applied this framework to multi-unit neural spiking data recorded using chronically implanted multi-electrode arrays from macaque primary motor cortex during a cued reaching, grasping and placing task. We show that, in line with previous work, the model identifies latent neural population states which are tightly linked to behavioural events, despite the model being trained without any information about event timing. The association between these states and corresponding behaviour is consistent across multiple days of recording. Notably, this consistency is not observed in the case of a single-level HMM, which fails to generalise across distinct recording sessions. The utility and stability of this approach is demonstrated using a previously learned task, but this multilevel Bayesian HMM framework would be especially suited for future studies of long-term plasticity in neural populations.
Collapse
Affiliation(s)
- Sebastien Kirchherr
- Institut des Sciences Cognitives Marc Jeannerod, CNRS UMR 5229, Bron, France
- Université Claude Bernard Lyon 1, Université de Lyon, France
| | | | - Gino Coudé
- Institut des Sciences Cognitives Marc Jeannerod, CNRS UMR 5229, Bron, France
- Université Claude Bernard Lyon 1, Université de Lyon, France
- Inovarion, Paris, France
| | - Marco Bimbi
- Institut des Sciences Cognitives Marc Jeannerod, CNRS UMR 5229, Bron, France
- Université Claude Bernard Lyon 1, Université de Lyon, France
| | - Pier F Ferrari
- Institut des Sciences Cognitives Marc Jeannerod, CNRS UMR 5229, Bron, France
- Université Claude Bernard Lyon 1, Université de Lyon, France
| | - Emmeke Aarts
- Department of Methodology and Statistics, Universiteit Utrecht, Utrecht, Netherlands
| | - James J Bonaiuto
- Institut des Sciences Cognitives Marc Jeannerod, CNRS UMR 5229, Bron, France
- Université Claude Bernard Lyon 1, Université de Lyon, France
| |
Collapse
|
13
|
Luan L, Yin R, Zhu H, Xie C. Emerging Penetrating Neural Electrodes: In Pursuit of Large Scale and Longevity. Annu Rev Biomed Eng 2023; 25:185-205. [PMID: 37289556 PMCID: PMC11078330 DOI: 10.1146/annurev-bioeng-090622-050507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Penetrating neural electrodes provide a powerful approach to decipher brain circuitry by allowing for time-resolved electrical detections of individual action potentials. This unique capability has contributed tremendously to basic and translational neuroscience, enabling both fundamental understandings of brain functions and applications of human prosthetic devices that restore crucial sensations and movements. However, conventional approaches are limited by the scarce number of available sensing channels and compromised efficacy over long-term implantations. Recording longevity and scalability have become the most sought-after improvements in emerging technologies. In this review, we discuss the technological advances in the past 5-10 years that have enabled larger-scale, more detailed, and longer-lasting recordings of neural circuits at work than ever before. We present snapshots of the latest advances in penetration electrode technology, showcase their applications in animal models and humans, and outline the underlying design principles and considerations to fuel future technological development.
Collapse
Affiliation(s)
- Lan Luan
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
| | - Rongkang Yin
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
| | - Hanlin Zhu
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
| |
Collapse
|
14
|
Franklin ME, Bennett C, Arboite M, Alvarez-Ciara A, Corrales N, Verdelus J, Dietrich WD, Keane RW, de Rivero Vaccari JP, Prasad A. Activation of inflammasomes and their effects on neuroinflammation at the microelectrode-tissue interface in intracortical implants. Biomaterials 2023; 297:122102. [PMID: 37015177 PMCID: PMC10614166 DOI: 10.1016/j.biomaterials.2023.122102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/16/2023] [Accepted: 03/23/2023] [Indexed: 03/30/2023]
Abstract
Invasive neuroprosthetics rely on microelectrodes (MEs) to record or stimulate the activity of large neuron assemblies. However, MEs are subjected to tissue reactivity in the central nervous system (CNS) due to the foreign body response (FBR) that contribute to chronic neuroinflammation and ultimately result in ME failure. An endogenous, acute set of mechanisms responsible for the recognition and targeting of foreign objects, called the innate immune response, immediately follows the ME implant-induced trauma. Inflammasomes are multiprotein structures that play a critical role in the initiation of an innate immune response following CNS injuries. The activation of inflammasomes facilitates a range of innate immune response cascades and results in neuroinflammation and programmed cell death. Despite our current understanding of inflammasomes, their roles in the context of neural device implantation remain unknown. In this study, we implanted a non-functional Utah electrode array (UEA) into the rat somatosensory cortex and studied the inflammasome signaling and the corresponding downstream effects on inflammatory cytokine expression and the inflammasome-mediated cell death mechanism of pyroptosis. Our results not only demonstrate the continuous activation of inflammasomes and their contribution to neuroinflammation at the electrode-tissue interface but also reveal the therapeutic potential of targeting inflammasomes to attenuate the FBR in invasive neuroprosthetics.
Collapse
Affiliation(s)
- Melissa E Franklin
- Department of Biomedical Engineering, University of Miami, Miami, FL, USA
| | - Cassie Bennett
- Department of Biomedical Engineering, University of Miami, Miami, FL, USA
| | - Maelle Arboite
- Department of Biomedical Engineering, University of Miami, Miami, FL, USA
| | | | - Natalie Corrales
- Department of Biomedical Engineering, University of Miami, Miami, FL, USA
| | - Jennifer Verdelus
- Department of Biomedical Engineering, University of Miami, Miami, FL, USA
| | - W Dalton Dietrich
- Department of Biomedical Engineering, University of Miami, Miami, FL, USA; Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; The Miami Project to Cure Paralysis, University of Miami, Miami, FL, USA
| | - Robert W Keane
- The Miami Project to Cure Paralysis, University of Miami, Miami, FL, USA; Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA; Center for Cognitive Neuroscience and Aging University of Miami Miller School of Medicine, Miami, FL, USA
| | - Juan Pablo de Rivero Vaccari
- The Miami Project to Cure Paralysis, University of Miami, Miami, FL, USA; Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL, USA; Center for Cognitive Neuroscience and Aging University of Miami Miller School of Medicine, Miami, FL, USA
| | - Abhishek Prasad
- Department of Biomedical Engineering, University of Miami, Miami, FL, USA; The Miami Project to Cure Paralysis, University of Miami, Miami, FL, USA.
| |
Collapse
|
15
|
Shen K, Chen O, Edmunds JL, Piech DK, Maharbiz MM. Translational opportunities and challenges of invasive electrodes for neural interfaces. Nat Biomed Eng 2023; 7:424-442. [PMID: 37081142 DOI: 10.1038/s41551-023-01021-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 02/15/2023] [Indexed: 04/22/2023]
Abstract
Invasive brain-machine interfaces can restore motor, sensory and cognitive functions. However, their clinical adoption has been hindered by the surgical risk of implantation and by suboptimal long-term reliability. In this Review, we highlight the opportunities and challenges of invasive technology for clinically relevant electrophysiology. Specifically, we discuss the characteristics of neural probes that are most likely to facilitate the clinical translation of invasive neural interfaces, describe the neural signals that can be acquired or produced by intracranial electrodes, the abiotic and biotic factors that contribute to their failure, and emerging neural-interface architectures.
Collapse
Affiliation(s)
- Konlin Shen
- University of California, Berkeley - University of California, San Francisco Graduate Program in Bioengineering, Berkeley, CA, USA.
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA.
| | - Oliver Chen
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
| | - Jordan L Edmunds
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
| | - David K Piech
- University of California, Berkeley - University of California, San Francisco Graduate Program in Bioengineering, Berkeley, CA, USA
| | - Michel M Maharbiz
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
- Department of Bioengineering, University of California, Berkeley, CA, USA
- Chan-Zuckerberg Biohub, San Francisco, CA, USA
| |
Collapse
|
16
|
Jeakle EN, Abbott JR, Usoro JO, Wu Y, Haghighi P, Radhakrishna R, Sturgill BS, Nakajima S, Thai TTD, Pancrazio JJ, Cogan SF, Hernandez-Reynoso AG. Chronic Stability of Local Field Potentials Using Amorphous Silicon Carbide Microelectrode Arrays Implanted in the Rat Motor Cortex. MICROMACHINES 2023; 14:680. [PMID: 36985087 PMCID: PMC10054633 DOI: 10.3390/mi14030680] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 06/18/2023]
Abstract
Implantable microelectrode arrays (MEAs) enable the recording of electrical activity of cortical neurons, allowing the development of brain-machine interfaces. However, MEAs show reduced recording capabilities under chronic conditions, prompting the development of novel MEAs that can improve long-term performance. Conventional planar, silicon-based devices and ultra-thin amorphous silicon carbide (a-SiC) MEAs were implanted in the motor cortex of female Sprague-Dawley rats, and weekly anesthetized recordings were made for 16 weeks after implantation. The spectral density and bandpower between 1 and 500 Hz of recordings were compared over the implantation period for both device types. Initially, the bandpower of the a-SiC devices and standard MEAs was comparable. However, the standard MEAs showed a consistent decline in both bandpower and power spectral density throughout the 16 weeks post-implantation, whereas the a-SiC MEAs showed substantially more stable performance. These differences in bandpower and spectral density between standard and a-SiC MEAs were statistically significant from week 6 post-implantation until the end of the study at 16 weeks. These results support the use of ultra-thin a-SiC MEAs to develop chronic, reliable brain-machine interfaces.
Collapse
Affiliation(s)
- Eleanor N. Jeakle
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Justin R. Abbott
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Joshua O. Usoro
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Yupeng Wu
- Department of Materials Science and Engineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Pegah Haghighi
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Rahul Radhakrishna
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Brandon S. Sturgill
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Shido Nakajima
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Teresa T. D. Thai
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Joseph J. Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Stuart F. Cogan
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Ana G. Hernandez-Reynoso
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| |
Collapse
|
17
|
Bergeron D, Iorio-Morin C, Bonizzato M, Lajoie G, Orr Gaucher N, Racine É, Weil AG. Use of Invasive Brain-Computer Interfaces in Pediatric Neurosurgery: Technical and Ethical Considerations. J Child Neurol 2023; 38:223-238. [PMID: 37116888 PMCID: PMC10226009 DOI: 10.1177/08830738231167736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 02/11/2023] [Accepted: 03/17/2023] [Indexed: 04/30/2023]
Abstract
Invasive brain-computer interfaces hold promise to alleviate disabilities in individuals with neurologic injury, with fully implantable brain-computer interface systems expected to reach the clinic in the upcoming decade. Children with severe neurologic disabilities, like quadriplegic cerebral palsy or cervical spine trauma, could benefit from this technology. However, they have been excluded from clinical trials of intracortical brain-computer interface to date. In this manuscript, we discuss the ethical considerations related to the use of invasive brain-computer interface in children with severe neurologic disabilities. We first review the technical hardware and software considerations for the application of intracortical brain-computer interface in children. We then discuss ethical issues related to motor brain-computer interface use in pediatric neurosurgery. Finally, based on the input of a multidisciplinary panel of experts in fields related to brain-computer interface (functional and restorative neurosurgery, pediatric neurosurgery, mathematics and artificial intelligence research, neuroengineering, pediatric ethics, and pragmatic ethics), we then formulate initial recommendations regarding the clinical use of invasive brain-computer interfaces in children.
Collapse
Affiliation(s)
- David Bergeron
- Division of Neurosurgery, Université de Montréal, Montreal, Québec, Canada
| | | | - Marco Bonizzato
- Electrical Engineering Department, Polytechnique Montréal, Montreal, Québec, Canada
- Neuroscience Department and Centre
interdisciplinaire de recherche sur le cerveau et l’apprentissage (CIRCA), Université de Montréal, Montréal, Québec, Canada
| | - Guillaume Lajoie
- Mathematics and Statistics Department, Université de Montréal, Montreal, Québec, Canada
- Mila - Québec AI Institute, Montréal,
Québec, Canada
| | - Nathalie Orr Gaucher
- Department of Pediatric Emergency
Medicine, CHU Sainte-Justine, Montréal, Québec, Canada
- Bureau de l’Éthique clinique, Faculté
de médecine de l’Université de Montréal, Montreal, Québec, Canada
| | - Éric Racine
- Pragmatic Research Unit, Institute de
Recherche Clinique de Montréal (IRCM), Montreal, Québec, Canada
- Department of Medicine and Department
of Social and Preventative Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Alexander G. Weil
- Division of Neurosurgery, Department
of Surgery, Centre Hospitalier Universitaire Sainte-Justine (CHUSJ), Département de
Pédiatrie, Université de Montréal, Montreal, Québec, Canada
- Department of Neuroscience, Université de Montréal, Montréal, Québec, Canada
- Brain and Development Research Axis,
CHU Sainte-Justine Research Center, Montréal, Québec, Canada
| |
Collapse
|
18
|
Patel PR, Welle EJ, Letner JG, Shen H, Bullard AJ, Caldwell CM, Vega-Medina A, Richie JM, Thayer HE, Patil PG, Cai D, Chestek CA. Utah array characterization and histological analysis of a multi-year implant in non-human primate motor and sensory cortices. J Neural Eng 2023; 20:10.1088/1741-2552/acab86. [PMID: 36595323 PMCID: PMC9954796 DOI: 10.1088/1741-2552/acab86] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/14/2022] [Indexed: 12/15/2022]
Abstract
Objective.The Utah array is widely used in both clinical studies and neuroscience. It has a strong track record of safety. However, it is also known that implanted electrodes promote the formation of scar tissue in the immediate vicinity of the electrodes, which may negatively impact the ability to record neural waveforms. This scarring response has been primarily studied in rodents, which may have a very different response than primate brain.Approach.Here, we present a rare nonhuman primate histological dataset (n= 1 rhesus macaque) obtained 848 and 590 d after implantation in two brain hemispheres. For 2 of 4 arrays that remained within the cortex, NeuN was used to stain for neuron somata at three different depths along the shanks. Images were filtered and denoised, with neurons then counted in the vicinity of the arrays as well as a nearby section of control tissue. Additionally, 3 of 4 arrays were imaged with a scanning electrode microscope to evaluate any materials damage that might be present.Main results.Overall, we found a 63% percent reduction in the number of neurons surrounding the electrode shanks compared to control areas. In terms of materials, the arrays remained largely intact with metal and Parylene C present, though tip breakage and cracks were observed on many electrodes.Significance.Overall, these results suggest that the tissue response in the nonhuman primate brain shows similar neuron loss to previous studies using rodents. Electrode improvements, for example using smaller or softer probes, may therefore substantially improve the tissue response and potentially improve the neuronal recording yield in primate cortex.
Collapse
Affiliation(s)
- Paras R. Patel
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Elissa J. Welle
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Joseph G. Letner
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Hao Shen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Autumn J. Bullard
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Ciara M. Caldwell
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Alexis Vega-Medina
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48019, United States of America,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America
| | - Julianna M. Richie
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Hope E. Thayer
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America
| | - Parag G. Patil
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America,Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America,Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America
| | - Dawen Cai
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America,Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, United States of America,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48019, United States of America
| | - Cynthia A. Chestek
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America,Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America,Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, United States of America,Robotics Program, University of Michigan, Ann Arbor, MI 48109, United States of America, Corresponding author:
| |
Collapse
|
19
|
Berger E, Brandes G, Reifenrath J, Lenarz T, Durisin M, Wissel K. In vitro impact of platinum nanoparticles on inner ear related cell culture models. PLoS One 2023; 18:e0284794. [PMID: 37093819 PMCID: PMC10124869 DOI: 10.1371/journal.pone.0284794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/07/2023] [Indexed: 04/25/2023] Open
Abstract
So far, it was supposed that the increase of electrical impedance following cochlear implant (CI) insertion was due to technical defects of the electrode, inflammatory and/or formation of scar tissue along the electrode. However, it was recently reported that corrosion of the platinum electrode contacts may be the reason for high impedances. It could be shown that platinum particles were stripped from the electrode surfaces. Its potential cytotoxic effects within the inner ear remains to be examined. In this study in vitro cell culture models of the mouse organ of Corti cell line (HEI-OC1) and the spiral ganglion (SG) cells derived from the cochleae neonatal rats were used to investigate the effects of the polyvinylpyrrolidone coated platinum nanoparticles (Pt-NPPVP, 3 nm) on cell metabolism, neuronal survival and neurite outgrowth. Our data revealed no decrease of the metabolic activity of the HEI-OC1 cells at Pt-NPPVP concentrations between 50-150 μg/ml. Also, staining with Calcein AM/EthD demonstrated prevalent presence of vital cells. As shown by transmission electron microscopy no Pt-NPPVP could be found at the cell surface or in the cytosol of the HEI-OC1 cells. Similarly, the SG cells exposed to 20-100 μg/ml Pt-NPPVP did not show any reduced survival rate and neurite outgrowth following staining of the neurofilament antigen even at the highest Pt-NPPVP concentration. Although the SG cells were exposed to Pt-NPPVP for further 72 h and 96 h immunocytochemical staining of the glial cells and fibroblasts presented normal cell morphology and growth independently of the cultivation period. Our data indicates that the used Pt-NPPVP do not trigger the cellular uptake and, thus, presumable do not initiate apoptotic pathways in cells of the organ of Corti cell line or the auditory nerve. The protection mechanisms to the Pt-NPPVP interactions remain to be clarified.
Collapse
Affiliation(s)
- Elisabeth Berger
- Hannover Medical School, Department of Otorhinolaryngology, Hannover, Germany
- Hannover Medical School, Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Gudrun Brandes
- Hannover Medical School, Institute of Neuroanatomy and Cell Biology, Center of Anatomy and Cell Biology, Hannover, Germany
| | - Janin Reifenrath
- Hannover Medical School, Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
- Hannover Medical School, Clinic for Orthopaedic Surgery, Hannover, Germany
| | - Thomas Lenarz
- Hannover Medical School, Department of Otorhinolaryngology, Hannover, Germany
- Hannover Medical School, Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Martin Durisin
- Hannover Medical School, Department of Otorhinolaryngology, Hannover, Germany
- Hannover Medical School, Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
- University Clinic of Otolaryngology, Head and Neck Surgery, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Kirsten Wissel
- Hannover Medical School, Department of Otorhinolaryngology, Hannover, Germany
- Hannover Medical School, Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| |
Collapse
|
20
|
Atherton E, Hu Y, Brown S, Papiez E, Ling V, Colvin V, Borton D. A 3D in vitro model of the device-tissue interface: Functional and structural symptoms of innate neuroinflammation are mitigated by antioxidant ceria nanoparticles. J Neural Eng 2022; 19. [PMID: 35447619 DOI: 10.1088/1741-2552/ac6908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 04/20/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The recording instability of neural implants due to neuroinflammation at the device-tissue interface is a primary roadblock to broad adoption of brain-machine interfaces. While a multiphasic immune response, marked by glial scaring, oxidative stress (OS), and neurodegeneration, is well-characterized, the independent contributions of systemic and local "innate" immune responses are not well-understood. We aimed to understand and mitigate the isolated the innate neuroinflammatory response to devices. APPROACH Three-dimensional primary neural cultures provide a unique environment for studying the drivers of neuroinflammation by decoupling the innate and systemic immune systems, while conserving an endogenous extracellular matrix and structural and functional network complexity. We created a three-dimensional in vitro model of the DTI by seeding primary cortical cells around microwires. Live imaging of both dye and AAV-mediated functional, structural, and lipid peroxidation fluorescence was employed to characterize the neuroinflammatory response. MAIN RESULTS Live imaging of microtissues over time revealed independent innate neuroinflammation, marked by increased OS, decreased neuronal density, and increased functional connectivity. We demonstrated the use of this model for therapeutic screening by directly applying drugs to neural tissue, bypassing low bioavailability through the in vivo blood brain barrier. As there is growing interest in long-acting antioxidant therapies, we tested efficacy of "perpetual" antioxidant ceria nanoparticles, which reduced OS, increased neuronal density, and protected functional connectivity. SIGNIFICANCE Our 3D in vitro model of the device-tissue interface exhibited symptoms of OS-mediated innate neuroinflammation, indicating a significant local immune response to devices. The dysregulation of functional connectivity of microcircuits surround implants suggests the presence of an observer effect, in which the process of recording neural activity may fundamentally change the neural signal. Finally, the demonstration of antioxidant ceria nanoparticle treatment exhibited substantial promise as a neuroprotective and anti-inflammatory treatment strategy.
Collapse
Affiliation(s)
- Elaina Atherton
- School of Engineering, Brown University, 182 Hope Street, Providence, RI 02912, USA, Providence, Rhode Island, 02912, UNITED STATES
| | - Yue Hu
- Department of Chemistry, Brown University, 182 Hope Street, Providence, RI 02912, USA, Providence, Rhode Island, 02912, UNITED STATES
| | - Sophie Brown
- School of Engineering, Brown University, 182 Hope Street, Providence, RI 02912, USA, Providence, Rhode Island, 02912, UNITED STATES
| | - Emily Papiez
- School of Engineering, Brown University, 182 Hope Street, Providence, RI 02912, USA, Providence, Rhode Island, 02912, UNITED STATES
| | - Vivian Ling
- Department of Chemistry, Brown University, 182 Hope Street, Providence, RI 02912, USA, Providence, Rhode Island, 02912, UNITED STATES
| | - Vicki Colvin
- Department of Chemistry, Brown University, 182 Hope Street, Providence, RI 02912, USA, Providence, Rhode Island, 02912, UNITED STATES
| | - David Borton
- School of Engineering, Brown University, 182 Hope Street, Providence, RI 02912, USA, Providence, Rhode Island, 02912, UNITED STATES
| |
Collapse
|
21
|
Kiang L, Woodington B, Carnicer-Lombarte A, Malliaras G, Barone DG. Spinal cord bioelectronic interfaces: opportunities in neural recording and clinical challenges. J Neural Eng 2022; 19. [PMID: 35320780 DOI: 10.1088/1741-2552/ac605f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/23/2022] [Indexed: 11/11/2022]
Abstract
Bioelectronic stimulation of the spinal cord has demonstrated significant progress in restoration of motor function in spinal cord injury (SCI). The proximal, uninjured spinal cord presents a viable target for the recording and generation of control signals to drive targeted stimulation. Signals have been directly recorded from the spinal cord in behaving animals and correlated with limb kinematics. Advances in flexible materials, electrode impedance and signal analysis will allow SCR to be used in next-generation neuroprosthetics. In this review, we summarize the technological advances enabling progress in SCR and describe systematically the clinical challenges facing spinal cord bioelectronic interfaces and potential solutions, from device manufacture, surgical implantation to chronic effects of foreign body reaction and stress-strain mismatches between electrodes and neural tissue. Finally, we establish our vision of bi-directional closed-loop spinal cord bioelectronic bypass interfaces that enable the communication of disrupted sensory signals and restoration of motor function in SCI.
Collapse
Affiliation(s)
- Lei Kiang
- Orthopaedic Surgery, Singapore General Hospital, Outram Road, Singapore, Singapore, 169608, SINGAPORE
| | - Ben Woodington
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Alejandro Carnicer-Lombarte
- Clinical Neurosciences, University of Cambridge, Bioelectronics Laboratory, Cambridge, CB2 0PY, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - George Malliaras
- University of Cambridge, University of Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Damiano G Barone
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| |
Collapse
|
22
|
Oldroyd P, Malliaras GG. Achieving long-term stability of thin-film electrodes for neurostimulation. Acta Biomater 2022; 139:65-81. [PMID: 34020055 DOI: 10.1016/j.actbio.2021.05.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/06/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022]
Abstract
Implantable electrodes that can reliably measure brain activity and deliver an electrical stimulus to a target tissue are increasingly employed to treat various neurological diseases and neuropsychiatric disorders. Flexible thin-film electrodes have gained attention over the past few years to minimise invasiveness and damage upon implantation. Research has previously focused on optimising the electrode's electrical and mechanical properties; however, their chronic stability must be validated to translate electrodes from a research to a clinical application. Neurostimulation electrodes, which actively inject charge, have yet to reliably demonstrate continuous functionality for ten years or more in vivo, the accepted metric for clinical viability. Long-term stability can only be achieved if the focus switches to investigating how and why such devices fail. Unfortunately, there is a field-wide reluctance to investigate device stability and failures, which hinders device optimisation. This review surveys thin-film electrode designs with a focus on adhesion between electrode layers and the interactions with the surrounding environment. A comprehensive summary of the abiotic failure modes faced by such electrodes is presented, and to encourage investigation, systematic methods for analysing their origin are recommended. Finally, approaches to reducing the likelihood of device failure are offered. STATEMENT OF SIGNIFICANCE: Neural electrodes that can deliver an electrical stimulus to a target tissue are widely used to treat various neurological diseases. Essential to the function of these electrodes is the ability to safely stimulate the target tissue for extended periods (> 10 years); however, this has not yet been clinically achieved. The key to achieving long-term stability is an increased understanding of electrode interactions with the surrounding tissue and subsequent systematic analysis of their failure modes. This review highlights the need for a change in the approach to investigating electrode failure, and in doing so summarizes the common ways in which neural electrodes fail, methods for identifying them and approaches to preventing them.
Collapse
|
23
|
Vėbraitė I, Hanein Y. Soft Devices for High-Resolution Neuro-Stimulation: The Interplay Between Low-Rigidity and Resolution. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:675744. [PMID: 35047928 PMCID: PMC8757739 DOI: 10.3389/fmedt.2021.675744] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/14/2021] [Indexed: 12/27/2022] Open
Abstract
The field of neurostimulation has evolved over the last few decades from a crude, low-resolution approach to a highly sophisticated methodology entailing the use of state-of-the-art technologies. Neurostimulation has been tested for a growing number of neurological applications, demonstrating great promise and attracting growing attention in both academia and industry. Despite tremendous progress, long-term stability of the implants, their large dimensions, their rigidity and the methods of their introduction and anchoring to sensitive neural tissue remain challenging. The purpose of this review is to provide a concise introduction to the field of high-resolution neurostimulation from a technological perspective and to focus on opportunities stemming from developments in materials sciences and engineering to reduce device rigidity while optimizing electrode small dimensions. We discuss how these factors may contribute to smaller, lighter, softer and higher electrode density devices.
Collapse
Affiliation(s)
- Ieva Vėbraitė
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yael Hanein
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
24
|
Woeppel K, Hughes C, Herrera AJ, Eles JR, Tyler-Kabara EC, Gaunt RA, Collinger JL, Cui XT. Explant Analysis of Utah Electrode Arrays Implanted in Human Cortex for Brain-Computer-Interfaces. Front Bioeng Biotechnol 2021; 9:759711. [PMID: 34950640 PMCID: PMC8688945 DOI: 10.3389/fbioe.2021.759711] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/29/2021] [Indexed: 01/11/2023] Open
Abstract
Brain-computer interfaces are being developed to restore movement for people living with paralysis due to injury or disease. Although the therapeutic potential is great, long-term stability of the interface is critical for widespread clinical implementation. While many factors can affect recording and stimulation performance including electrode material stability and host tissue reaction, these factors have not been investigated in human implants. In this clinical study, we sought to characterize the material integrity and biological tissue encapsulation via explant analysis in an effort to identify factors that influence electrophysiological performance. We examined a total of six Utah arrays explanted from two human participants involved in intracortical BCI studies. Two platinum (Pt) arrays were implanted for 980 days in one participant (P1) and two Pt and two iridium oxide (IrOx) arrays were implanted for 182 days in the second participant (P2). We observed that the recording quality followed a similar trend in all six arrays with an initial increase in peak-to-peak voltage during the first 30–40 days and gradual decline thereafter in P1. Using optical and two-photon microscopy we observed a higher degree of tissue encapsulation on both arrays implanted for longer durations in participant P1. We then used scanning electron microscopy and energy dispersive X-ray spectroscopy to assess material degradation. All measures of material degradation for the Pt arrays were found to be more prominent in the participant with a longer implantation time. Two IrOx arrays were subjected to brief survey stimulations, and one of these arrays showed loss of iridium from most of the stimulated sites. Recording performance appeared to be unaffected by this loss of iridium, suggesting that the adhesion of IrOx coating may have been compromised by the stimulation, but the metal layer did not detach until or after array removal. In summary, both tissue encapsulation and material degradation were more pronounced in the arrays that were implanted for a longer duration. Additionally, these arrays also had lower signal amplitude and impedance. New biomaterial strategies that minimize fibrotic encapsulation and enhance material stability should be developed to achieve high quality recording and stimulation for longer implantation periods.
Collapse
Affiliation(s)
- Kevin Woeppel
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States
| | - Christopher Hughes
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs, Pittsburgh, PA, United States
| | - Angelica J Herrera
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs, Pittsburgh, PA, United States
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Elizabeth C Tyler-Kabara
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Department of Neurosurgery, The University of Texas at Austin, Austin, TX, United States
| | - Robert A Gaunt
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs, Pittsburgh, PA, United States.,Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jennifer L Collinger
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs, Pittsburgh, PA, United States.,Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Center for the Neural Basis of Cognition, Pittsburgh, PA, United States
| |
Collapse
|
25
|
Zabcikova M, Koudelkova Z, Jasek R, Navarro JJL. Recent Advances and Current Trends in Brain-Computer Interface (BCI) Research and Their Applications. Int J Dev Neurosci 2021; 82:107-123. [PMID: 34939217 DOI: 10.1002/jdn.10166] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 11/16/2021] [Accepted: 12/18/2021] [Indexed: 11/06/2022] Open
Abstract
Brain-Computer Interface (BCI) provides direct communication between the brain and an external device. BCI systems have become a trendy field of research in recent years. These systems can be used in a variety of applications to help both disabled and healthy people. Concerning significant BCI progress, we may assume that these systems are not very far from real-world applications. This review has taken into account current trends in BCI research. In this survey, one hundred most cited articles from the WOS database were selected over the last four years. This survey is divided into several sectors. These sectors are Medicine, Communication and Control, Entertainment, and Other BCI applications. The application area, recording method, signal acquisition types, and countries of origin have been identified in each article. This survey provides an overview of the BCI articles published from 2016 to 2020 and their current trends and advances in different application areas.
Collapse
Affiliation(s)
- Martina Zabcikova
- Department of Informatics and Artificial Intelligence, Faculty of Applied Informatics, Tomas Bata University in Zlin, Zlin, Czech Republic
| | - Zuzana Koudelkova
- Department of Informatics and Artificial Intelligence, Faculty of Applied Informatics, Tomas Bata University in Zlin, Zlin, Czech Republic
| | - Roman Jasek
- Department of Informatics and Artificial Intelligence, Faculty of Applied Informatics, Tomas Bata University in Zlin, Zlin, Czech Republic
| | - José Javier Lorenzo Navarro
- Departamento de Informática y Sistemas, Instituto Universitario de Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| |
Collapse
|
26
|
Chapman CAR, Cuttaz EA, Tahirbegi B, Novikov A, Petkos K, Koutsoftidis S, Drakakis EM, Goding JA, Green RA. Flexible Networks of Patterned Conducting Polymer Nanowires for Fully Polymeric Bioelectronics. ADVANCED NANOBIOMED RESEARCH 2021. [DOI: 10.1002/anbr.202100102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
| | - Estelle A. Cuttaz
- Department of Bioengineering Imperial College London South Kensington London SW7 2AZ UK
| | - Bogachan Tahirbegi
- Department of Bioengineering Imperial College London South Kensington London SW7 2AZ UK
| | - Alexey Novikov
- Department of Bioengineering Imperial College London South Kensington London SW7 2AZ UK
| | - Konstantinos Petkos
- Department of Bioengineering Imperial College London South Kensington London SW7 2AZ UK
- Center for Neurotechnology Imperial College London Prince Consort Road London SW7 2AZ UK
| | - Simos Koutsoftidis
- Department of Bioengineering Imperial College London South Kensington London SW7 2AZ UK
| | - Emmanuel M. Drakakis
- Department of Bioengineering Imperial College London South Kensington London SW7 2AZ UK
- Center for Neurotechnology Imperial College London Prince Consort Road London SW7 2AZ UK
| | - Josef A. Goding
- Department of Bioengineering Imperial College London South Kensington London SW7 2AZ UK
| | - Rylie A. Green
- Department of Bioengineering Imperial College London South Kensington London SW7 2AZ UK
| |
Collapse
|
27
|
Fabrication of Planar Microelectrode Array Using Laser-Patterned ITO and SU-8. MICROMACHINES 2021; 12:mi12111347. [PMID: 34832760 PMCID: PMC8621540 DOI: 10.3390/mi12111347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/27/2021] [Accepted: 10/28/2021] [Indexed: 01/09/2023]
Abstract
For several decades, microelectrode array (MEA) has been a powerful tool for in vitro neural electrophysiology because it provides a unique approach for monitoring the activity of a number of neurons over time. Due to the various applications of MEAs with different types of cells and tissues, there is an increasing need to customize the electrode designs. However, the fabrication of conventional MEAs requires several microfabrication procedures of deposition, etching, and photolithography. In this study, we proposed a simple fabrication method with a laser-patterned indium tin oxide (ITO) conductor and SU-8 photoresist insulation. Unlike in a conventional metal patterning process, only the outlines of ITO conductors are ablated by laser without removing background ITO. Insulation is achieved simply via SU-8 photolithography. The electrode sites are electroplated with iridium oxide (IrOX) to improve the electrochemical properties. The fabricated MEAs are electrochemically characterized and the stability of insulation is also confirmed by impedance monitoring for three weeks. Dissociated neurons of rat hippocampi are cultured on MEAs to verify the biocompatibility and the capacity for extracellular neural recording. The electrochemical and electrophysiological results with the fabricated MEAs are similar to those from conventional SiNX-insulated MEAs. Therefore, the proposed MEA with laser-patterned ITO and SU-8 is cost-effective and equivalently feasible compared with the conventional MEAs fabricated using thin-film microfabrication techniques.
Collapse
|
28
|
Development of a magnetically aligned regenerative tissue-engineered electronic nerve interface for peripheral nerve applications. Biomaterials 2021; 279:121212. [PMID: 34717196 DOI: 10.1016/j.biomaterials.2021.121212] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 10/11/2021] [Accepted: 10/20/2021] [Indexed: 01/18/2023]
Abstract
Peripheral nerve injuries can be debilitating to motor and sensory function, with severe cases often resulting in complete limb amputation. Over the past two decades, prosthetic limb technology has rapidly advanced to provide users with crude motor control of up to 20° of freedom; however, the nerve-interfacing technology required to provide high movement selectivity has not progressed at the same rate. The work presented here focuses on the development of a magnetically aligned regenerative tissue-engineered electronic nerve interface (MARTEENI) that combines polyimide "threads" encapsulated within a magnetically aligned hydrogel scaffold. The technology exploits tissue-engineered strategies to address concerns over traditional peripheral nerve interfaces including poor axonal sampling through the nerve and rigid substrates. A magnetically templated hydrogel is used to physically support the polyimide threads while also promoting regeneration in close proximity to the electrode sites on the polyimide. This work demonstrates the utility of magnetic templating for use in tuning the mechanical properties of hydrogel scaffolds to match the stiffness of native nerve tissue while providing an aligned substrate for Schwann cell migration in vitro. MARTEENI devices were fabricated and implanted within a 5-mm-long rat sciatic-nerve transection model to assess regeneration at 6 and 12 weeks. MARTEENI devices do not disrupt tissue remodeling and show axon densities equivalent to fresh tissue controls around the polyimide substrates. Devices are observed to have attenuated foreign-body responses around the polyimide threads. It is expected that future studies with functional MARTEENI devices will be able to record and stimulate single axons with high selectivity and low stimulation regimes.
Collapse
|
29
|
Lamont C, Grego T, Nanbakhsh K, Shah Idil A, Giagka V, Vanhoestenberghe A, Cogan S, Donaldson N. Silicone encapsulation of thin-film SiO x, SiO xN yand SiC for modern electronic medical implants: a comparative long-term ageing study. J Neural Eng 2021; 18:055003. [PMID: 33752188 PMCID: PMC8208634 DOI: 10.1088/1741-2552/abf0d6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/22/2021] [Indexed: 02/03/2023]
Abstract
Objective.Ensuring the longevity of implantable devices is critical for their clinical usefulness. This is commonly achieved by hermetically sealing the sensitive electronics in a water impermeable housing, however, this method limits miniaturisation. Alternatively, silicone encapsulation has demonstrated long-term protection of implanted thick-film electronic devices. However, much of the current conformal packaging research is focused on more rigid coatings, such as parylene, liquid crystal polymers and novel inorganic layers. Here, we consider the potential of silicone to protect implants using thin-film technology with features 33 times smaller than thick-film counterparts.Approach.Aluminium interdigitated comb structures under plasma-enhanced chemical vapour deposited passivation (SiOx, SiOxNy, SiOxNy+ SiC) were encapsulated in medical grade silicones, with a total of six passivation/silicone combinations. Samples were aged in phosphate-buffered saline at 67 ∘C for up to 694 days under a continuous ±5 V biphasic waveform. Periodic electrochemical impedance spectroscopy measurements monitored for leakage currents and degradation of the metal traces. Fourier-transform infrared spectroscopy, x-ray photoelectron spectroscopy, focused-ion-beam and scanning-electron- microscopy were employed to determine any encapsulation material changes.Main results.No silicone delamination, passivation dissolution, or metal corrosion was observed during ageing. Impedances greater than 100 GΩ were maintained between the aluminium tracks for silicone encapsulation over SiOxNyand SiC passivations. For these samples the only observed failure mode was open-circuit wire bonds. In contrast, progressive hydration of the SiOxcaused its resistance to decrease by an order of magnitude.Significance.These results demonstrate silicone encapsulation offers excellent protection to thin-film conducting tracks when combined with appropriate inorganic thin films. This conclusion corresponds to previous reliability studies of silicone encapsulation in aqueous environments, but with a larger sample size. Therefore, we believe silicone encapsulation to be a realistic means of providing long-term protection for the circuits of implanted electronic medical devices.
Collapse
Affiliation(s)
- C Lamont
- Implanted Devices Group, Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, United Kingdom,Author to whom any correspondence should be addressed
| | - T Grego
- Implanted Devices Group, Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, United Kingdom
| | - K Nanbakhsh
- Department of Microelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Delft, The Netherlands
| | - A Shah Idil
- Implanted Devices Group, Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, United Kingdom
| | - V Giagka
- Department of Microelectronics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Delft, The Netherlands,
Department of System Integration and Interconnection Technologies, Fraunhofer Institute for Reliability and Micro-integration IZM, Berlin, Germany
| | - A Vanhoestenberghe
- Implanted Devices Group, Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, United Kingdom,
Institute of Orthopaedics and Musculoskeletal Science, RNOH Trust, University College London, Stanmore, United Kingdom
| | - S Cogan
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, United States of America
| | - N Donaldson
- Implanted Devices Group, Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, United Kingdom
| |
Collapse
|
30
|
Colachis SC, Dunlap CF, Annetta NV, Tamrakar SM, Bockbrader MA, Friedenberg DA. Long-term intracortical microelectrode array performance in a human: a 5 year retrospective analysis. J Neural Eng 2021; 18. [PMID: 34352736 DOI: 10.1088/1741-2552/ac1add] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 08/05/2021] [Indexed: 12/18/2022]
Abstract
Objective. Brain-computer interfaces (BCIs) that record neural activity using intracortical microelectrode arrays (MEAs) have shown promise for mitigating disability associated with neurological injuries and disorders. While the chronic performance and failure modes of MEAs have been well studied and systematically described in non-human primates, there is far less reported about long-term MEA performance in humans. Our group has collected one of the largest neural recording datasets from a Utah MEA in a human subject, spanning over 5 years (2014-2019). Here we present both long-term signal quality and BCI performance as well as highlight several acute signal disruption events observed during the clinical study.Approach. Long-term Utah array performance was evaluated by analyzing neural signal metric trends and decoding accuracy for tasks regularly performed across 448 clinical recording sessions. For acute signal disruptions, we identify or hypothesize the root cause of the disruption, show how the disruption manifests in the collected data, and discuss potential identification and mitigation strategies for the disruption.Main results. Neural signal quality metrics deteriorated rapidly within the first year, followed by a slower decline through the remainder of the study. Nevertheless, BCI performance remained high 5 years after implantation, which is encouraging for the translational potential of this technology as an assistive device. We also present examples of unanticipated signal disruptions during chronic MEA use, which are critical to detect as BCI technology progresses toward home usage.Significance. Our work fills a gap in knowledge around long-term MEA performance in humans, providing longevity and efficacy data points to help characterize the performance of implantable neural sensors in a human population. The trial was registered on ClinicalTrials.gov (Identifier NCT01997125) and conformed to institutional requirements for the conduct of human subjects research.
Collapse
Affiliation(s)
- Samuel C Colachis
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH 43201, United States of America.,Contributed equally
| | - Collin F Dunlap
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH 43201, United States of America.,Center for Neuromodulation, The Ohio State University, Columbus, OH 43210, United States of America.,Department of Physical Medicine and Rehabilitation, The Ohio State University, Columbus, OH 43210, United States of America.,Contributed equally
| | - Nicholas V Annetta
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH 43201, United States of America
| | - Sanjay M Tamrakar
- Health Analytics, Battelle Memorial Institute, Columbus, OH 43201, United States of America
| | - Marcia A Bockbrader
- Center for Neuromodulation, The Ohio State University, Columbus, OH 43210, United States of America.,Department of Physical Medicine and Rehabilitation, The Ohio State University, Columbus, OH 43210, United States of America
| | - David A Friedenberg
- Health Analytics, Battelle Memorial Institute, Columbus, OH 43201, United States of America
| |
Collapse
|
31
|
Intracortical Microelectrode Array Unit Yield under Chronic Conditions: A Comparative Evaluation. MICROMACHINES 2021; 12:mi12080972. [PMID: 34442594 PMCID: PMC8400387 DOI: 10.3390/mi12080972] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 01/01/2023]
Abstract
While microelectrode arrays (MEAs) offer the promise of elucidating functional neural circuitry and serve as the basis for a cortical neuroprosthesis, the challenge of designing and demonstrating chronically reliable technology remains. Numerous studies report “chronic” data but the actual time spans and performance measures corresponding to the experimental work vary. In this study, we reviewed the experimental durations that constitute chronic studies across a range of MEA types and animal species to gain an understanding of the widespread variability in reported study duration. For rodents, which are the most commonly used animal model in chronic studies, we examined active electrode yield (AEY) for different array types as a means to contextualize the study duration variance, as well as investigate and interpret the performance of custom devices in comparison to conventional MEAs. We observed wide-spread variance within species for the chronic implantation period and an AEY that decayed linearly in rodent models that implanted commercially-available devices. These observations provide a benchmark for comparing the performance of new technologies and highlight the need for consistency in chronic MEA studies. Additionally, to fully derive performance under chronic conditions, the duration of abiotic failure modes, biological processes induced by indwelling probes, and intended application of the device are key determinants.
Collapse
|
32
|
Szymanski LJ, Kellis S, Liu CY, Jones KT, Andersen RA, Commins D, Lee B, McCreery DB, Miller CA. Neuropathological effects of chronically implanted, intracortical microelectrodes in a tetraplegic patient. J Neural Eng 2021; 18. [PMID: 34314384 DOI: 10.1088/1741-2552/ac127e] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/08/2021] [Indexed: 11/12/2022]
Abstract
Objective.Intracortical microelectrode arrays (MEA) can be used as part of a brain-machine interface system to provide sensory feedback control of an artificial limb to assist persons with tetraplegia. Variability in functionality of electrodes has been reported but few studies in humans have examined the impact of chronic brain tissue responses revealed postmortem on electrode performancein vivo. Approach.In a tetraplegic man, recording MEAs were implanted into the anterior intraparietal area and Brodmann's area 5 (BA5) of the posterior parietal cortex and a recording and stimulation array was implanted in BA1 of the primary somatosensory cortex (S1). The participant expired from unrelated causes seven months after MEA implantation. The underlying tissue of two of the three devices was processed for histology and electrophysiological recordings were assessed.Main results.Recordings of neuronal activity were obtained from all three MEAs despite meningeal encapsulation. However, the S1 array had a greater encapsulation, yielded lower signal quality than the other arrays and failed to elicit somatosensory percepts with electrical stimulation. Histological examination of tissues underlying S1 and BA5 implant sites revealed localized leptomeningeal proliferation and fibrosis, lymphocytic infiltrates, astrogliosis, and foreign body reaction around the electrodes. The BA5 recording site showed focal cerebral microhemorrhages and leptomeningeal vascular ectasia. The S1 site showed focal tissue damage including vascular recanalization, neuronal loss, and extensive subcortical white matter necrosis. The tissue response at the S1 site included hemorrhagic-induced injury suggesting a likely mechanism for reduced function of the S1 implant.Significance.Our findings are similar to those from animal studies with chronic intracortical implants and suggest that vascular disruption and microhemorrhage during device implantation are important contributors to overall array and individual electrode performance and should be a topic for future device development to mitigate tissue responses. Neurosurgical considerations are also discussed.
Collapse
Affiliation(s)
- Linda J Szymanski
- Department of Pathology, Keck USC School of Medicine, Los Angeles, CA, United States of America.,Department of Pathology and Laboratory Medicine, Children's Hospital of Los Angeles, Los Angeles, CA, United States of America
| | - Spencer Kellis
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States of America.,Tianqiao and Chrissy Chen Brain-Machine Interface Center, Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA, United States of America.,Department of Neurosurgery, Keck USC School of Medicine, Los Angeles, CA, United States of America.,USC Neurorestoration Center, Keck USC School of Medicine, Los Angeles, CA, United States of America
| | - Charles Y Liu
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States of America.,Department of Neurosurgery, Keck USC School of Medicine, Los Angeles, CA, United States of America.,USC Neurorestoration Center, Keck USC School of Medicine, Los Angeles, CA, United States of America
| | - Kymry T Jones
- Department of Pathology, Keck USC School of Medicine, Los Angeles, CA, United States of America
| | - Richard A Andersen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States of America.,Tianqiao and Chrissy Chen Brain-Machine Interface Center, Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA, United States of America
| | - Deborah Commins
- Department of Pathology, Keck USC School of Medicine, Los Angeles, CA, United States of America
| | - Brian Lee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States of America.,Department of Neurosurgery, Keck USC School of Medicine, Los Angeles, CA, United States of America.,USC Neurorestoration Center, Keck USC School of Medicine, Los Angeles, CA, United States of America
| | - Douglas B McCreery
- Huntington Medical Research Institute, Pasadena, CA, United States of America
| | - Carol A Miller
- Department of Pathology, Keck USC School of Medicine, Los Angeles, CA, United States of America
| |
Collapse
|
33
|
Feng C, Frewin CL, Tanjil MRE, Everly R, Bieber J, Kumar A, Wang MC, Saddow SE. A Flexible a-SiC-Based Neural Interface Utilizing Pyrolyzed-Photoresist Film (C) Active Sites. MICROMACHINES 2021; 12:821. [PMID: 34357231 PMCID: PMC8304835 DOI: 10.3390/mi12070821] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/07/2021] [Accepted: 07/10/2021] [Indexed: 01/06/2023]
Abstract
Carbon containing materials, such as graphene, carbon-nanotubes (CNT), and graphene oxide, have gained prominence as possible electrodes in implantable neural interfaces due to their excellent conductive properties. While carbon is a promising electrochemical interface, many fabrication processes are difficult to perform, leading to issues with large scale device production and overall repeatability. Here we demonstrate that carbon electrodes and traces constructed from pyrolyzed-photoresist-film (PPF) when combined with amorphous silicon carbide (a-SiC) insulation could be fabricated with repeatable processes which use tools easily available in most semiconductor facilities. Directly forming PPF on a-SiC simplified the fabrication process which eliminates noble metal evaporation/sputtering and lift-off processes on small features. PPF electrodes in oxygenated phosphate buffered solution at pH 7.4 demonstrated excellent electrochemical charge storage capacity (CSC) of 14.16 C/cm2, an impedance of 24.8 ± 0.4 kΩ, and phase angle of -35.9 ± 0.6° at 1 kHz with a 1.9 kµm2 recording site area.
Collapse
Affiliation(s)
- Chenyin Feng
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA;
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | | | - Md Rubayat-E Tanjil
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | - Richard Everly
- Nanotechnology Research & Education Center, University of South Florida, Tampa, FL 33620, USA; (R.E.); (J.B.)
| | - Jay Bieber
- Nanotechnology Research & Education Center, University of South Florida, Tampa, FL 33620, USA; (R.E.); (J.B.)
| | - Ashok Kumar
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | - Michael Cai Wang
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | - Stephen E. Saddow
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA;
- Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA
| |
Collapse
|
34
|
Sridharan A, Muthuswamy J. Soft, Conductive, Brain-Like, Coatings at Tips of Microelectrodes Improve Electrical Stability under Chronic, In Vivo Conditions. MICROMACHINES 2021; 12:761. [PMID: 34203234 PMCID: PMC8306035 DOI: 10.3390/mi12070761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/22/2021] [Accepted: 06/25/2021] [Indexed: 01/27/2023]
Abstract
Several recent studies have reported improved histological and electrophysiological outcomes with soft neural interfaces that have elastic moduli ranging from 10 s of kPa to hundreds of MPa. However, many of these soft interfaces use custom fabrication processes. We test the hypothesis that a readily adoptable fabrication process for only coating the tips of microelectrodes with soft brain-like (elastic modulus of ~5 kPa) material improves the long-term electrical performance of neural interfaces. Conventional tungsten microelectrodes (n = 9 with soft coatings and n = 6 uncoated controls) and Pt/Ir microelectrodes (n = 16 with soft coatings) were implanted in six animals for durations ranging from 5 weeks to over 1 year in a subset of rats. Electrochemical impedance spectroscopy was used to assess the quality of the brain tissue-electrode interface under chronic conditions. Neural recordings were assessed for unit activity and signal quality. Electrodes with soft, silicone coatings showed relatively stable electrical impedance characteristics over 6 weeks to >1 year compared to the uncoated control electrodes. Single unit activity recorded by coated electrodes showed larger peak-to-peak amplitudes and increased number of detectable neurons compared to uncoated controls over 6-7 weeks. We demonstrate the feasibility of using a readily translatable process to create brain-like soft interfaces that can potentially overcome variable performance associated with chronic rigid neural interfaces.
Collapse
Affiliation(s)
| | - Jit Muthuswamy
- School of Biological and Health Systems Engineering, Ira A. Fulton School of Engineering, Arizona State University, Tempe, AZ 85287-9709, USA;
| |
Collapse
|
35
|
Thielen B, Meng E. A comparison of insertion methods for surgical placement of penetrating neural interfaces. J Neural Eng 2021; 18:10.1088/1741-2552/abf6f2. [PMID: 33845469 PMCID: PMC8600966 DOI: 10.1088/1741-2552/abf6f2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/12/2021] [Indexed: 02/07/2023]
Abstract
Many implantable electrode arrays exist for the purpose of stimulating or recording electrical activity in brain, spinal, or peripheral nerve tissue, however most of these devices are constructed from materials that are mechanically rigid. A growing body of evidence suggests that the chronic presence of these rigid probes in the neural tissue causes a significant immune response and glial encapsulation of the probes, which in turn leads to gradual increase in distance between the electrodes and surrounding neurons. In recording electrodes, the consequence is the loss of signal quality and, therefore, the inability to collect electrophysiological recordings long term. In stimulation electrodes, higher current injection is required to achieve a comparable response which can lead to tissue and electrode damage. To minimize the impact of the immune response, flexible neural probes constructed with softer materials have been developed. These flexible probes, however, are often not strong enough to be inserted on their own into the tissue, and instead fail via mechanical buckling of the shank under the force of insertion. Several strategies have been developed to allow the insertion of flexible probes while minimizing tissue damage. It is critical to keep these strategies in mind during probe design in order to ensure successful surgical placement. In this review, existing insertion strategies will be presented and evaluated with respect to surgical difficulty, immune response, ability to reach the target tissue, and overall limitations of the technique. Overall, the majority of these insertion techniques have only been evaluated for the insertion of a single probe and do not quantify the accuracy of probe placement. More work needs to be performed to evaluate and optimize insertion methods for accurate placement of devices and for devices with multiple probes.
Collapse
Affiliation(s)
- Brianna Thielen
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States of America
| | - Ellis Meng
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States of America
| |
Collapse
|
36
|
Carnicer-Lombarte A, Chen ST, Malliaras GG, Barone DG. Foreign Body Reaction to Implanted Biomaterials and Its Impact in Nerve Neuroprosthetics. Front Bioeng Biotechnol 2021; 9:622524. [PMID: 33937212 PMCID: PMC8081831 DOI: 10.3389/fbioe.2021.622524] [Citation(s) in RCA: 142] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/19/2021] [Indexed: 12/04/2022] Open
Abstract
The implantation of any foreign material into the body leads to the development of an inflammatory and fibrotic process-the foreign body reaction (FBR). Upon implantation into a tissue, cells of the immune system become attracted to the foreign material and attempt to degrade it. If this degradation fails, fibroblasts envelop the material and form a physical barrier to isolate it from the rest of the body. Long-term implantation of medical devices faces a great challenge presented by FBR, as the cellular response disrupts the interface between implant and its target tissue. This is particularly true for nerve neuroprosthetic implants-devices implanted into nerves to address conditions such as sensory loss, muscle paralysis, chronic pain, and epilepsy. Nerve neuroprosthetics rely on tight interfacing between nerve tissue and electrodes to detect the tiny electrical signals carried by axons, and/or electrically stimulate small subsets of axons within a nerve. Moreover, as advances in microfabrication drive the field to increasingly miniaturized nerve implants, the need for a stable, intimate implant-tissue interface is likely to quickly become a limiting factor for the development of new neuroprosthetic implant technologies. Here, we provide an overview of the material-cell interactions leading to the development of FBR. We review current nerve neuroprosthetic technologies (cuff, penetrating, and regenerative interfaces) and how long-term function of these is limited by FBR. Finally, we discuss how material properties (such as stiffness and size), pharmacological therapies, or use of biodegradable materials may be exploited to minimize FBR to nerve neuroprosthetic implants and improve their long-term stability.
Collapse
Affiliation(s)
- Alejandro Carnicer-Lombarte
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Shao-Tuan Chen
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - George G. Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Damiano G. Barone
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
37
|
Cuttaz EA, Chapman CAR, Syed O, Goding JA, Green RA. Stretchable, Fully Polymeric Electrode Arrays for Peripheral Nerve Stimulation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2004033. [PMID: 33898185 PMCID: PMC8061359 DOI: 10.1002/advs.202004033] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/19/2021] [Indexed: 05/08/2023]
Abstract
There is a critical need to transition research level flexible polymer bioelectronics toward the clinic by demonstrating both reliability in fabrication and stable device performance. Conductive elastomers (CEs) are composites of conductive polymers in elastomeric matrices that provide both flexibility and enhanced electrochemical properties compared to conventional metallic electrodes. This work focuses on the development of nerve cuff devices and the assessment of the device functionality at each development stage, from CE material to fully polymeric electrode arrays. Two device types are fabricated by laser machining of a thick and thin CE sheet variant on an insulative polydimethylsiloxane substrate and lamination into tubing to produce pre-curled cuffs. Device performance and stability following sterilization and mechanical loading are compared to a state-of-the-art stretchable metallic nerve cuff. The CE cuffs are found to be electrically and mechanically stable with improved charge transfer properties compared to the commercial cuff. All devices are applied to an ex vivo whole sciatic nerve and shown to be functional, with the CE cuffs demonstrating superior charge transfer and electrochemical safety in the biological environment.
Collapse
Affiliation(s)
- Estelle A. Cuttaz
- Department of BioengineeringImperial CollegeSouth KensingtonLondonSW7 2AZUK
| | | | - Omaer Syed
- Department of BioengineeringImperial CollegeSouth KensingtonLondonSW7 2AZUK
| | - Josef A. Goding
- Department of BioengineeringImperial CollegeSouth KensingtonLondonSW7 2AZUK
| | - Rylie A. Green
- Department of BioengineeringImperial CollegeSouth KensingtonLondonSW7 2AZUK
| |
Collapse
|
38
|
Cai L, Gutruf P. Soft, Wireless and subdermally implantable recording and neuromodulation tools. J Neural Eng 2021; 18. [PMID: 33607646 DOI: 10.1088/1741-2552/abe805] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 02/19/2021] [Indexed: 12/14/2022]
Abstract
Progress in understanding neuronal interaction and circuit behavior of the central and peripheral nervous system strongly relies on the advancement of tools that record and stimulate with high fidelity and specificity. Currently, devices used in exploratory research predominantly utilize cables or tethers to provide pathways for power supply, data communication, stimulus delivery and recording, which constrains the scope and use of such devices. In particular, the tethered connection, mechanical mismatch to surrounding soft tissues and bones frustrate the interface leading to irritation and limitation of motion of the subject, which in the case of fundamental and preclinical studies, impacts naturalistic behaviors of animals and precludes the use in experiments involving social interaction and ethologically relevant three-dimensional environments, limiting the use of current tools to mostly rodents and exclude species such as birds and fish. This review explores the current state-of-the-art in wireless, subdermally implantable tools that quantitively expand capabilities in analysis and perturbation of the central and peripheral nervous system by removing tethers and externalized features of implantable neuromodulation and recording tools. Specifically, the review explores power harvesting strategies, wireless communication schemes, and soft materials and mechanics that enable the creation of such devices and discuss their capabilities in the context of freely-behaving subjects. Highlights of this class of devices includes wireless battery-free and fully implantable operation with capabilities in cell specific recording, multimodal neural stimulation and electrical, optogenetic and pharmacological neuromodulation capabilities. We conclude with discussion on translation of such technologies which promises routes towards broad dissemination.
Collapse
Affiliation(s)
- Le Cai
- Biomedical Engineering, University of Arizona, 1230 N Cherry Ave., Tucson, Arizona, 85719, UNITED STATES
| | - Philipp Gutruf
- Biomedical Engineering, University of Arizona, 1230 N Cherry Ave., Tucson, Arizona, 85719, UNITED STATES
| |
Collapse
|
39
|
Shepherd RK, Carter P, Dalrymple A, Enke YL, Wise AK, Nguyen T, Firth J, Thompson A, Fallon JB. Platinum dissolution and tissue response following long-term electrical stimulation at high charge densities. J Neural Eng 2021; 18. [PMID: 33578409 DOI: 10.1088/1741-2552/abe5ba] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/12/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Established guidelines for safe levels of electrical stimulation for neural prostheses are based on a limited range of the stimulus parameters used clinically. Recent studies have reported particulate platinum (Pt) associated with long-term clinical use of these devices, highlighting the need for more carefully defined safety limits. We previously reported no adverse effects of Pt corrosion products in the cochleae of guinea pigs following 4 weeks of electrical stimulation using charge densities far greater than the published safe limits for cochlear implants. The present study examines the histopathological effects of Pt within the cochlea following continuous stimulation at a charge density well above the defined safe limits for periods up to 6 months. APPROACH Six cats were bilaterally implanted with Pt electrode arrays and unilaterally stimulated using charge balanced current pulses at a charge density of 267 C/cm2/phase using a tripolar electrode configuration. Electrochemical measurements were made throughout the implant duration and evoked potentials recorded at the outset and on completion of the stimulation program. Cochleae were examined histologically for particulate Pt, tissue response, and auditory nerve survival; electrodes were examined for surface corrosion; and cochlea, brain, kidney, and liver tissue analysed for trace levels of Pt. MAIN RESULTS Chronic stimulation resulted in both a significant increase in tissue response and particulate Pt within the tissue capsule surrounding the electrode array compared with implanted, unstimulated control cochleae. Importantly, there was no stimulus-induced loss of auditory neurons or increase in evoked potential thresholds. Stimulated electrodes were significantly more corroded compared with unstimulated electrodes. Trace analysis revealed Pt in both stimulated and control cochleae although significantly greater levels were detected within stimulated cochleae. There was no evidence of Pt in brain or liver; however, trace levels of Pt were recorded in the kidneys of two animals. Finally, increased charge storage capacity and charge injection limit reflected the more extensive electrode corrosion associated with stimulated electrodes. SIGNIFICANCE Long-term electrical stimulation of Pt electrodes at a charge density well above existing safety limits and nearly an order of magnitude higher than levels used clinically, does not adversely affect the auditory neuron population or reduce neural function, despite a stimulus-induced tissue response and the accumulation of Pt corrosion product. The mechanism resulting in Pt within the unstimulated cochlea is unclear, while the level of Pt observed systemically following stimulation at these very high charge densities does not appear to be of clinical significance.
Collapse
Affiliation(s)
- Robert K Shepherd
- Bionics Institute, 384-388 Albert Street East, Melbourne, Victoria, Melbourne, Victoria, 3002, AUSTRALIA
| | - Paul Carter
- Cochlear Ltd., 1 University Avenue, Macquarie University, Macquarie Park, New South Wales, 2109, AUSTRALIA
| | - Ashley Dalrymple
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania, 15213, UNITED STATES
| | - Ya Lang Enke
- Cochlear Ltd, 1 University Avenue, Macquarie University, Macquarie University, New South Wales, 2109, AUSTRALIA
| | - Andrew K Wise
- Bionics Institute, 384-388 Albert Street East, Melbourne, Vic 3002, Melbourne, Victoria, 3002, AUSTRALIA
| | - Trung Nguyen
- Bionics Institute, 384-388 Albert St, East Melbourne, Melbourne, Victoria, 3002, AUSTRALIA
| | - James Firth
- Bionics Institute, 384-388 Albert St, East Melbourne, Melbourne, Victoria, 3002, AUSTRALIA
| | - Alex Thompson
- Bionics Institute, 384-388 Albert St, East Melbourne, East Melbourne, Victoria, 3002, AUSTRALIA
| | - James B Fallon
- Bionics Institute, , 384-388 Albert Street East, Melbourne, Vic 3002, Fitzroy, Victoria, 3056, AUSTRALIA
| |
Collapse
|
40
|
Ferrari LM, Rodríguez-Meana B, Bonisoli A, Cutrone A, Micera S, Navarro X, Greco F, Del Valle J. All-Polymer Printed Low-Cost Regenerative Nerve Cuff Electrodes. Front Bioeng Biotechnol 2021; 9:615218. [PMID: 33644015 PMCID: PMC7902501 DOI: 10.3389/fbioe.2021.615218] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022] Open
Abstract
Neural regeneration after lesions is still limited by several factors and new technologies are developed to address this issue. Here, we present and test in animal models a new regenerative nerve cuff electrode (RnCE). It is based on a novel low-cost fabrication strategy, called "Print and Shrink", which combines the inkjet printing of a conducting polymer with a heat-shrinkable polymer substrate for the development of a bioelectronic interface. This method allows to produce miniaturized regenerative cuff electrodes without the use of cleanroom facilities and vacuum based deposition methods, thus highly reducing the production costs. To fully proof the electrodes performance in vivo we assessed functional recovery and adequacy to support axonal regeneration after section of rat sciatic nerves and repair with RnCE. We investigated the possibility to stimulate the nerve to activate different muscles, both in acute and chronic scenarios. Three months after implantation, RnCEs were able to stimulate regenerated motor axons and induce a muscular response. The capability to produce fully-transparent nerve interfaces provided with polymeric microelectrodes through a cost-effective manufacturing process is an unexplored approach in neuroprosthesis field. Our findings pave the way to the development of new and more usable technologies for nerve regeneration and neuromodulation.
Collapse
Affiliation(s)
- Laura M Ferrari
- Center for Micro-BioRobotics @SSSA, Istituto Italiano di Tecnologia, Pontedera, Italy.,The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pontedera, Italy.,Université Côte d'Azur, INRIA, Sophia Antipolis, France
| | - Bruno Rodríguez-Meana
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, Spain
| | - Alberto Bonisoli
- Center for Micro-BioRobotics @SSSA, Istituto Italiano di Tecnologia, Pontedera, Italy.,The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pontedera, Italy
| | - Annarita Cutrone
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pontedera, Italy
| | - Silvestro Micera
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pontedera, Italy.,Bertarelli Foundation Chair in Translational NeuroEngineering, Center for Neuroprosthetics and Institute of Bioengineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, Spain
| | - Francesco Greco
- Center for Micro-BioRobotics @SSSA, Istituto Italiano di Tecnologia, Pontedera, Italy.,Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Graz, Austria.,Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Jaume Del Valle
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, Spain
| |
Collapse
|
41
|
Rihani R, Tasnim N, Javed M, Usoro JO, D'Souza TM, Ware TH, Pancrazio JJ. Liquid Crystalline Polymers: Opportunities to Shape Neural Interfaces. Neuromodulation 2021; 25:1259-1267. [PMID: 33501705 DOI: 10.1111/ner.13364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/21/2020] [Accepted: 01/05/2021] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Polymers have emerged as constituent materials for the creation of microscale neural interfaces; however, limitations regarding water permeability, delamination, and material degradation impact polymeric device robustness. Liquid crystal polymers (LCPs) have molecular order like a solid but with the fluidity of a liquid, resulting in a unique material, with properties including low water permeability, chemical inertness, and mechanical toughness. The objective of this article is to review the state-of-the-art regarding the use of LCPs in neural interface applications and discuss challenges and opportunities where this class of materials can advance the field of neural interfaces. MATERIALS AND METHODS This review article focuses on studies that leverage LCP materials to interface with the nervous system in vivo. A comprehensive literature search was performed using PubMed, Web of Science (Clarivate Analytics), and Google Scholar. RESULTS There have been recent efforts to create neural interfaces that leverage the material advantages of LCPs. The literature offers examples of LCP as a basis for implantable medical devices and neural interfaces in the form of planar electrode arrays for retinal prosthetic, electrocorticography applications, and cuff-like structures for interfacing the peripheral nerve. In addition, there have been efforts to create penetrating intracortical devices capable of microstimulation and resolution of biopotentials. Recent work with a subclass of LCPs, namely liquid crystal elastomers, demonstrates that it is possible to create devices with features that deploy away from a central implantation site to interface with a volume of tissue while offering the possibility of minimizing tissue damage. CONCLUSION We envision the creation of novel microscale neural interfaces that leverage the physical properties of LCPs and have the capability of deploying within neural tissue for enhanced integration and performance.
Collapse
Affiliation(s)
- Rashed Rihani
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Nishat Tasnim
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Mahjabeen Javed
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.,Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Joshua O Usoro
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Tania M D'Souza
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Taylor H Ware
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.,Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA.,Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| |
Collapse
|
42
|
Evers J, Lowery M. The Active Electrode in the Living Brain: The Response of the Brain Parenchyma to Chronically Implanted Deep Brain Stimulation Electrodes. Oper Neurosurg (Hagerstown) 2021; 20:131-140. [PMID: 33074305 DOI: 10.1093/ons/opaa326] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/10/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Deep brain stimulation is an established symptomatic surgical therapy for Parkinson disease, essential tremor, and a number of other movement and neuropsychiatric disorders. The well-established foreign body response around implanted electrodes is marked by gliosis, neuroinflammation, and neurodegeneration. However, how this response changes with the application of chronic stimulation is less well-understood. OBJECTIVE To integrate the most recent evidence from basic science, patient, and postmortem studies on the effect of such an "active" electrode on the parenchyma of the living brain. METHODS A thorough and in-part systematic literature review identified 49 papers. RESULTS Increased electrode-tissue impedance is consistently observed in the weeks following electrode implantation, stabilizing at approximately 3 to 6 mo. Lower impedance values are observed around stimulated implanted electrodes when compared with unstimulated electrodes. A temporary reduction in impedance has also been observed in response to stimulation in nonhuman primates. Postmortem studies from patients confirm the presence of a fibrous sheath, astrocytosis, neuronal loss, and neuroinflammation in the immediate vicinity of the electrode. When comparing stimulated and unstimulated electrodes directly, there is some evidence across animal and patient studies of altered neurodegeneration and neuroinflammation around stimulated electrodes. CONCLUSION Establishing how stimulation influences the electrical and histological properties of the surrounding tissue is critical in understanding how these factors contribute to DBS efficacy, and in controlling symptoms and side effects. Understanding these complex issues will aid in the development of future neuromodulation systems that are optimized for the tissue environment and required stimulation protocols.
Collapse
Affiliation(s)
- Judith Evers
- School of Electrical and Electronic Engineering, University College Dublin, Dublin, Ireland.,CÚRAM SFI Research Centre for Medical Devices, National University of Ireland Galway, Galway, Ireland
| | - Madeleine Lowery
- School of Electrical and Electronic Engineering, University College Dublin, Dublin, Ireland.,CÚRAM SFI Research Centre for Medical Devices, National University of Ireland Galway, Galway, Ireland
| |
Collapse
|
43
|
Harris A. Understanding Charge Transfer on the Clinically Used Conical Utah Electrode Array: Charge Storage Capacity, Electrochemical Impedance Spectroscopy and Effective Electrode Area. J Neural Eng 2021; 18. [PMID: 33401255 DOI: 10.1088/1741-2552/abd897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 01/05/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The Utah electrode is used for pre/clinical studies on neural recording and stimulation. Anecdotal and empirical reports on their performance have been made, resulting in variable testing methods. An in depth investigation was performed to understand the electrochemical behaviour and charge transfer mechanisms occurring on these clinically important electrodes. APPROACH Platinum and iridium electrodes were assessed by cyclic voltammetry and electrochemical impedance spectroscopy. The effective electrode area was measured by reduction of Ru(NH3)63+. MAIN RESULTS Pristine Utah electrodes have little to no oxide present and the surface roughness is very low. Pristine iridium electrodes pass charge through capacitance and oxide formation. Hydride and anion adsorption occurs on the platinum electrode. Anodic current oxidises both metal surfaces, altering the charge transfer mechanisms at the electrode-solution interface. The charge storage capacity depends on measurement technique and electrode structure, providing no information on charge transfer mechanisms. Electrode oxidation increases pseudocapacitance, reducing impedance. Charge transfer was non-homogeneous, most likely due to the electrode geometry enhancing charge density at the electrode tip and base. Oxidation of the electrode surface enhanced charge transfer inhomogeneity. The effective electrode area could be measured by reduction of Ru(NH3)63+ and calculated with a finite cone geometry. SIGNIFICANCE Increasing electrode pseudocapacitance, demonstrated by metal oxidation, reduces impedance. Increasing electrode capacitance offers a potential route to reducing thermal noise and increasing signal-to-noise ratio of neural recording. The effective electrode area of conical electrodes can be measured. The charge density of the conical electrode was greater than expected on a planar disc electrode, indicating modification of electrode geometry can increase an electrodes safe charge injection capacity. In vivo electrochemical measurements often don't include sufficient details to understand the electrode behaviour. Electrode oxidation most likely accounts for a significant amount of variation in previously published Utah electrode impedance data.
Collapse
Affiliation(s)
- Alex Harris
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Aikenhead Centre for Medical Discovery, Melbourne, Victoria, 3065, AUSTRALIA
| |
Collapse
|
44
|
Bennett C, Álvarez-Ciara A, Franklin M, Dietrich WD, Prasad A. The complement cascade at the Utah microelectrode-tissue interface. Biomaterials 2021; 268:120583. [PMID: 33310540 PMCID: PMC7856077 DOI: 10.1016/j.biomaterials.2020.120583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/16/2020] [Accepted: 11/25/2020] [Indexed: 01/05/2023]
Abstract
Devices implanted within the central nervous system (CNS) are subjected to tissue reactivity due to the lack of biocompatibility between implanted material and the cells' microenvironment. Studies have attributed blood-brain barrier disruption, inflammation, and oxidative stress as main contributing factors that lead to electrode recording failure. The complement cascade is a part of the innate immunity that focuses on recognizing and targeting foreign objects; however, its role in the context of neural implants is substantially unknown. In this study, we implanted a non-functional 4x4 Utah microelectrode array (UEA) into the somatosensory cortex and studied the complement cascade via combined gene and immunohistochemistry quantification at acute (48-h), sub-acute (1-week), and early chronic (4-weeks) time points. The results of this study demonstrate the activation and continuation of the complement cascade at the electrode-tissue interface, illustrating the therapeutic potential of modulating the foreign body response via the complement cascade.
Collapse
Affiliation(s)
- Cassie Bennett
- Department of Biomedical Engineering, University of Miami, FL, USA
| | | | - Melissa Franklin
- Department of Biomedical Engineering, University of Miami, FL, USA
| | | | - Abhishek Prasad
- Department of Biomedical Engineering, University of Miami, FL, USA; The Miami Project to Cure Paralysis, University of Miami, FL, USA.
| |
Collapse
|
45
|
Vandekerckhove B, Missinne J, Vonck K, Bauwens P, Verplancke R, Boon P, Raedt R, Vanfleteren J. Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain. MICROMACHINES 2020; 12:38. [PMID: 33396287 PMCID: PMC7824489 DOI: 10.3390/mi12010038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 12/25/2022]
Abstract
Epilepsy is a chronic, neurological disorder affecting millions of people every year. The current available pharmacological and surgical treatments are lacking in overall efficacy and cause side-effects like cognitive impairment, depression, tremor, abnormal liver and kidney function. In recent years, the application of optogenetic implants have shown promise to target aberrant neuronal circuits in epilepsy with the advantage of both high spatial and temporal resolution and high cell-specificity, a feature that could tackle both the efficacy and side-effect problems in epilepsy treatment. Optrodes consist of electrodes to record local field potentials and an optical component to modulate neurons via activation of opsin expressed by these neurons. The goal of optogenetics in epilepsy is to interrupt seizure activity in its earliest state, providing a so-called closed-loop therapeutic intervention. The chronic implantation in vivo poses specific demands for the engineering of therapeutic optrodes. Enzymatic degradation and glial encapsulation of implants may compromise long-term recording and sufficient illumination of the opsin-expressing neural tissue. Engineering efforts for optimal optrode design have to be directed towards limitation of the foreign body reaction by reducing the implant's elastic modulus and overall size, while still providing stable long-term recording and large-area illumination, and guaranteeing successful intracerebral implantation. This paper presents an overview of the challenges and recent advances in the field of electrode design, neural-tissue illumination, and neural-probe implantation, with the goal of identifying a suitable candidate to be incorporated in a therapeutic approach for long-term treatment of epilepsy patients.
Collapse
Affiliation(s)
- Bram Vandekerckhove
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Jeroen Missinne
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Kristl Vonck
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Pieter Bauwens
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Rik Verplancke
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Paul Boon
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Robrecht Raedt
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Jan Vanfleteren
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| |
Collapse
|
46
|
Bourrier A, Szarpak-Jankowska A, Veliev F, Olarte-Hernandez R, Shkorbatova P, Bonizzato M, Rey E, Barraud Q, Briançon-Marjollet A, Auzely R, Courtine G, Bouchiat V, Delacour C. Introducing a biomimetic coating for graphene neuroelectronics: toward in-vivoapplications. Biomed Phys Eng Express 2020; 7. [PMID: 35125348 DOI: 10.1088/2057-1976/ab42d6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 09/09/2019] [Indexed: 11/12/2022]
Abstract
Electronic micro and nano-devices are suitable tools to monitor the activity of many individual neurons over mesoscale networks. However the inorganic materials currently used in microelectronics are barely accepted by neural cells and tissues, thus limiting both the sensor lifetime and efficiency. In particular, penetrating intracortical probes face high failure rate because of a wide immune response of cells and tissues. This adverse reaction called gliosis leads to the rejection of the implanted probe after few weeks and prevent long-lasting recordings of cortical neurons. Such acceptance issue impedes the realization of many neuro-rehabilitation projects. To overcome this, graphene and related carbon-based materials have attracted a lot of interest regarding their positive impact on the adhesion and regeneration of neurons, and their ability to provide high-sensitive electronic devices, such as graphene field effect transistor (G-FET). Such devices can also be implemented on numerous suitable substrates including soft substrates to match the mechanical compliance of cells and tissues, improving further the biocompatibility of the implants. Thus, using graphene as a coating and sensing device material could significantly enhance the acceptance of intracortical probes. However, such a thin monolayer of carbon atoms could be teared off during manipulation and insertion within the brain, and could also display degradation over time. In this work, we have investigated the ability to protect graphene with a natural, biocompatible and degradable polymeric film derivated from hyaluronic acid (HA). We demonstrate that HA-based coatings can be deposited over a wide range of substrates, including intracortical probes and graphene FET arrays without altering the underlying device material, its biocompatibility and sensitivity. Moreover, we show that this coating can be monitoredin situby quantifying the number of deposited charges with the G-FET arrays. The reported graphene functionalization offers promising alternatives for improving the acceptance of various neural interfaces.
Collapse
Affiliation(s)
- Antoine Bourrier
- Institut Néel, CNRS & Université Grenoble Alpes, 38042 Grenoble, France
| | | | - Farida Veliev
- Institut Néel, CNRS & Université Grenoble Alpes, 38042 Grenoble, France
| | | | - Polina Shkorbatova
- Center for Neuroprosthetics and Brain-Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Campus Biotech CH-1202 Geneva, Switzerland
| | - Marco Bonizzato
- Center for Neuroprosthetics and Brain-Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Campus Biotech CH-1202 Geneva, Switzerland
| | - Elodie Rey
- Center for Neuroprosthetics and Brain-Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Campus Biotech CH-1202 Geneva, Switzerland
| | - Quentin Barraud
- Center for Neuroprosthetics and Brain-Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Campus Biotech CH-1202 Geneva, Switzerland
| | - Anne Briançon-Marjollet
- Grenoble Alpes, HP2 Laboratory, Institut National de la Santé et de la Recherche Médicale U1042, Grenoble, France
| | - Rachel Auzely
- University Grenoble Alpes, CERMAV-CNRS, 38000 Grenoble, France
| | - Gregoire Courtine
- Center for Neuroprosthetics and Brain-Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Campus Biotech CH-1202 Geneva, Switzerland
| | - Vincent Bouchiat
- Institut Néel, CNRS & Université Grenoble Alpes, 38042 Grenoble, France
| | - Cécile Delacour
- Institut Néel, CNRS & Université Grenoble Alpes, 38042 Grenoble, France
| |
Collapse
|
47
|
Dunlap CF, Colachis SC, Meyers EC, Bockbrader MA, Friedenberg DA. Classifying Intracortical Brain-Machine Interface Signal Disruptions Based on System Performance and Applicable Compensatory Strategies: A Review. Front Neurorobot 2020; 14:558987. [PMID: 33162885 PMCID: PMC7581895 DOI: 10.3389/fnbot.2020.558987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022] Open
Abstract
Brain-machine interfaces (BMIs) record and translate neural activity into a control signal for assistive or other devices. Intracortical microelectrode arrays (MEAs) enable high degree-of-freedom BMI control for complex tasks by providing fine-resolution neural recording. However, chronically implanted MEAs are subject to a dynamic in vivo environment where transient or systematic disruptions can interfere with neural recording and degrade BMI performance. Typically, neural implant failure modes have been categorized as biological, material, or mechanical. While this categorization provides insight into a disruption's causal etiology, it is less helpful for understanding degree of impact on BMI function or possible strategies for compensation. Therefore, we propose a complementary classification framework for intracortical recording disruptions that is based on duration of impact on BMI performance and requirement for and responsiveness to interventions: (1) Transient disruptions interfere with recordings on the time scale of minutes to hours and can resolve spontaneously; (2) Reversible disruptions cause persistent interference in recordings but the root cause can be remedied by an appropriate intervention; (3) Irreversible compensable disruptions cause persistent or progressive decline in signal quality, but their effects on BMI performance can be mitigated algorithmically; and (4) Irreversible non-compensable disruptions cause permanent signal loss that is not amenable to remediation or compensation. This conceptualization of intracortical BMI disruption types is useful for highlighting specific areas for potential hardware improvements and also identifying opportunities for algorithmic interventions. We review recording disruptions that have been reported for MEAs and demonstrate how biological, material, and mechanical mechanisms of disruption can be further categorized according to their impact on signal characteristics. Then we discuss potential compensatory protocols for each of the proposed disruption classes. Specifically, transient disruptions may be minimized by using robust neural decoder features, data augmentation methods, adaptive machine learning models, and specialized signal referencing techniques. Statistical Process Control methods can identify reparable disruptions for rapid intervention. In-vivo diagnostics such as impedance spectroscopy can inform neural feature selection and decoding models to compensate for irreversible disruptions. Additional compensatory strategies for irreversible disruptions include information salvage techniques, data augmentation during decoder training, and adaptive decoding methods to down-weight damaged channels.
Collapse
Affiliation(s)
- Collin F. Dunlap
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH, United States
| | - Samuel C. Colachis
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH, United States
| | - Eric C. Meyers
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH, United States
| | - Marcia A. Bockbrader
- Department of Physical Medicine and Rehabilitation, The Ohio State University, Columbus, OH, United States
| | - David A. Friedenberg
- Advanced Analytics and Health Research, Battelle Memorial Institute, Columbus, OH, United States
| |
Collapse
|
48
|
Shepherd RK, Carter PM, Enke YL, Thompson A, Flynn B, Trang EP, Dalrymple AN, Fallon JB. Chronic intracochlear electrical stimulation at high charge densities: reducing platinum dissolution. J Neural Eng 2020; 17:056009. [DOI: 10.1088/1741-2552/abb7a6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
49
|
Dollt M, Reh M, Metzger M, Heusel G, Kriebel M, Bucher V, Zeck G. Low-Temperature Atomic Layer Deposited Oxide on Titanium Nitride Electrodes Enables Culture and Physiological Recording of Electrogenic Cells. Front Neurosci 2020; 14:552876. [PMID: 33071735 PMCID: PMC7530285 DOI: 10.3389/fnins.2020.552876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 08/13/2020] [Indexed: 12/27/2022] Open
Abstract
The performance of electrode arrays insulated by low-temperature atomic layer deposited (ALD) titanium dioxide (TiO2) or hafnium dioxide (HfO2) for culture of electrogenic cells and for recording of extracellular action potentials is investigated. If successful, such insulation may be considered to increase the stability of future neural implants. Here, insulation of titanium nitride electrodes of microelectrode arrays (MEAs) was performed using ALD of nanometer-sized TiO2 or hafnium oxide at low temperatures (100-200°C). The electrode properties, impedance, and leakage current were measured and compared. Although electrode insulation using ALD oxides increased the electrode impedance, it did not prevent stable, physiological recordings of electrical activity from electrogenic cells (cardiomyocytes and neurons). The insulation quality, estimated from leakage current measurements, was less than 100 nA/cm2 in a range of 3 V. Cardiomyocytes were successfully cultured and recorded after 5 days on the insulated MEAs with signal shapes similar to the recordings obtained using uncoated electrodes. Light-induced electrical activity of retinal ganglion cells was recorded using a complementary metal-oxide semiconductor-based MEA insulated with HfO2 without driving the recording electrode into saturation. The presented results demonstrate that low-temperature ALD-deposited TiO2 and hafnium oxide are biocompatible and biostable and enable physiological recordings. Our results indicate that nanometer-sized ALD insulation can be used to protect electrodes for long-term biological applications.
Collapse
Affiliation(s)
- Michele Dollt
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Miriam Reh
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
- Graduate School of Neural Information Processing/International Max Planck Research School, University of Tübingen, Reutlingen, Germany
| | - Michael Metzger
- Mechanical and Medical Engineering, Hochschule Furtwangen University, Villingen-Schwenningen, Germany
| | - Gerhard Heusel
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Martin Kriebel
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| | - Volker Bucher
- Mechanical and Medical Engineering, Hochschule Furtwangen University, Villingen-Schwenningen, Germany
| | - Günther Zeck
- Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
| |
Collapse
|
50
|
Apollo NV, Murphy B, Prezelski K, Driscoll N, Richardson AG, Lucas TH, Vitale F. Gels, jets, mosquitoes, and magnets: a review of implantation strategies for soft neural probes. J Neural Eng 2020; 17:041002. [PMID: 32759476 PMCID: PMC8152109 DOI: 10.1088/1741-2552/abacd7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Implantable neuroelectronic interfaces have enabled breakthrough advances in the clinical diagnosis and treatment of neurological disorders, as well as in fundamental studies of brain function, behavior, and disease. Intracranial electroencephalography (EEG) mapping with stereo-EEG (sEEG) depth electrodes is routinely adopted for precise epilepsy diagnostics and surgical treatment, while deep brain stimulation has become the standard of care for managing movement disorders. Intracortical microelectrode arrays for high-fidelity recordings of neural spiking activity have led to impressive demonstrations of the power of brain-machine interfaces for motor and sensory functional recovery. Yet, despite the rapid pace of technology development, the issue of establishing a safe, long-term, stable, and functional interface between neuroelectronic devices and the host brain tissue still remains largely unresolved. A body of work spanning at least the last 15 years suggests that safe, chronic integration between invasive electrodes and the brain requires a close match between the mechanical properties of man-made components and the neural tissue. In other words, the next generation of invasive electrodes should be soft and compliant, without sacrificing biological and chemical stability. Soft neuroelectronic interfaces, however, pose a new and significant surgical challenge: bending and buckling during implantation that can preclude accurate and safe device placement. In this topical review, we describe the next generation of soft electrodes and the surgical implantation methods for safe and precise insertion into brain structures. We provide an overview of the most recent innovations in the field of insertion strategies for flexible neural electrodes such as dissolvable or biodegradable carriers, microactuators, biologically-inspired support structures, and electromagnetic drives. In our analysis, we also highlight approaches developed in different fields, such as robotic surgery, which could be potentially adapted and translated to the insertion of flexible neural probes.
Collapse
Affiliation(s)
- Nicholas V Apollo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Brendan Murphy
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Kayla Prezelski
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Nicolette Driscoll
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Andrew G Richardson
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Timothy H Lucas
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Flavia Vitale
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Physical Medicine & Rehabilitation, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States of America
| |
Collapse
|