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Villa J, Cury J, Kessler L, Tan X, Richter CP. Enhancing biocompatibility of the brain-machine interface: A review. Bioact Mater 2024; 42:531-549. [PMID: 39308547 PMCID: PMC11416625 DOI: 10.1016/j.bioactmat.2024.08.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 08/05/2024] [Accepted: 08/27/2024] [Indexed: 09/25/2024] Open
Abstract
In vivo implantation of microelectrodes opens the door to studying neural circuits and restoring damaged neural pathways through direct electrical stimulation and recording. Although some neuroprostheses have achieved clinical success, electrode material properties, inflammatory response, and glial scar formation at the electrode-tissue interfaces affect performance and sustainability. Those challenges can be addressed by improving some of the materials' mechanical, physical, chemical, and electrical properties. This paper reviews materials and designs of current microelectrodes and discusses perspectives to advance neuroprosthetics performance.
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Affiliation(s)
- Jordan Villa
- Northwestern University-Feinberg School of Medicine, Department of Otolaryngology, USA
| | - Joaquin Cury
- Northwestern University-Feinberg School of Medicine, Department of Otolaryngology, USA
| | - Lexie Kessler
- Northwestern University-Feinberg School of Medicine, Department of Otolaryngology, USA
| | - Xiaodong Tan
- Northwestern University-Feinberg School of Medicine, Department of Otolaryngology, USA
- The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, USA
| | - Claus-Peter Richter
- Northwestern University-Feinberg School of Medicine, Department of Otolaryngology, USA
- The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, USA
- Department of Communication Sciences and Disorders, Northwestern University, USA
- Department of Biomedical Engineering, Northwestern University, USA
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2
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Yang Q, Wu B, Castagnola E, Pwint MY, Williams NP, Vazquez AL, Cui XT. Integrated Microprism and Microelectrode Array for Simultaneous Electrophysiology and Two-Photon Imaging across All Cortical Layers. Adv Healthc Mater 2024; 13:e2302362. [PMID: 38563704 PMCID: PMC11421982 DOI: 10.1002/adhm.202302362] [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: 07/24/2023] [Revised: 02/24/2024] [Indexed: 04/04/2024]
Abstract
Cerebral neural electronics play a crucial role in neuroscience research with increasing translational applications such as brain-computer interfaces for sensory input and motor output restoration. While widely utilized for decades, the understanding of the cellular mechanisms underlying this technology remains limited. Although two-photon microscopy (TPM) has shown great promise in imaging superficial neural electrodes, its application to deep-penetrating electrodes is technically difficult. Here, a novel device integrating transparent microelectrode arrays with glass microprisms, enabling electrophysiology recording and stimulation alongside TPM imaging across all cortical layers in a vertical plane, is introduced. Tested in Thy1-GCaMP6 mice for over 4 months, the integrated device demonstrates the capability for multisite electrophysiological recording/stimulation and simultaneous TPM calcium imaging. As a proof of concept, the impact of microstimulation amplitude, frequency, and depth on neural activation patterns is investigated using the setup. With future improvements in material stability and single unit yield, this multimodal tool greatly expands integrated electrophysiology and optical imaging from the superficial brain to the entire cortical column, opening new avenues for neuroscience research and neurotechnology development.
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Affiliation(s)
- Qianru Yang
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittburgh, PA, 15213, USA
- School of Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Bingchen Wu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittburgh, PA, 15213, USA
| | - Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Biomedical Engineering Department, Louisiana Tech University, Ruston, LA, 71272, USA
| | - May Yoon Pwint
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittburgh, PA, 15213, USA
| | - Nathaniel P Williams
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittburgh, PA, 15213, USA
| | - Alberto L Vazquez
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittburgh, PA, 15213, USA
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, 15219, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittburgh, PA, 15213, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, 15219, USA
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Mirkiani S, O’Sullivan CL, Roszko DA, Faridi P, Hu DS, Everaert DG, Toossi A, Kang R, Fang T, Tyreman N, Dalrymple AN, Robinson K, Uwiera RRE, Shah H, Fox R, Konrad PE, Mushahwar VK. Safety of mapping the motor networks in the spinal cord using penetrating microelectrodes in Yucatan minipigs. J Neurosurg Spine 2024; 41:292-304. [PMID: 38728765 PMCID: PMC11174925 DOI: 10.3171/2024.2.spine23757] [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: 07/08/2023] [Accepted: 02/21/2024] [Indexed: 05/12/2024]
Abstract
OBJECTIVE The goal of this study was to assess the safety of mapping spinal cord locomotor networks using penetrating stimulation microelectrodes in Yucatan minipigs (YMPs) as a clinically translational animal model. METHODS Eleven YMPs were trained to walk up and down a straight line. Motion capture was performed, and electromyographic (EMG) activity of hindlimb muscles was recorded during overground walking. The YMPs underwent a laminectomy and durotomy to expose the lumbar spinal cord. Using an ultrasound-guided stereotaxic frame, microelectrodes were inserted into the spinal cord in 8 animals. Pial cuts were made to prevent tissue dimpling before microelectrode insertion. Different locations within the lumbar enlargement were electrically stimulated to map the locomotor networks. The remaining 3 YMPs served as sham controls, receiving the laminectomy, durotomy, and pial cuts but not microelectrode insertion. The Porcine Thoracic Injury Behavioral Scale (PTIBS) and hindlimb reflex assessment results were recorded for 4 weeks postoperatively. Overground gait kinematics and hindlimb EMG activity were recorded again at weeks 3 and 4 postoperatively and compared with preoperative measures. The animals were euthanized at the end of week 4, and the lumbar spinal cords were extracted and preserved for immunohistochemical analysis. RESULTS All YMPs showed transient deficits in hindlimb function postoperatively. Except for 1 YMP in the experimental group, all animals regained normal ambulation and balance (PTIBS score 10) at the end of weeks 3 and 4. One animal in the experimental group showed gait and balance deficits by week 4 (PTIBS score 4). This animal was excluded from the kinematics and EMG analyses. Overground gait kinematic measures and EMG activity showed no significant (p > 0.05) differences between preoperative and postoperative values, and between the experimental and sham groups. Less than 5% of electrode tracks were visible in the tissue analysis of the animals in the experimental group. There was no statistically significant difference in damage caused by pial cuts between the experimental and sham groups. Tissue damage due to the pial cuts was more frequently observed in immunohistochemical analyses than microelectrode tracks. CONCLUSIONS These findings suggest that mapping spinal locomotor networks in porcine models can be performed safely, without lasting damage to the spinal cord.
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Affiliation(s)
- Soroush Mirkiani
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
| | - Carly L. O’Sullivan
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
| | - David A. Roszko
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Ontario, Canada
| | - Pouria Faridi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
| | - David S. Hu
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Dirk G. Everaert
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Amirali Toossi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Ryan Kang
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
| | - Tongzhou Fang
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
| | - Neil Tyreman
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Ashley N. Dalrymple
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Kevin Robinson
- School of Physical Therapy, Belmont University, Nashville, Tennessee
| | - Richard R. E. Uwiera
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Hamid Shah
- Vanderbilt University Medical Center, Nashville, Tennessee
| | - Richard Fox
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
- Division of Neurosurgery, Department of Surgery, University of Alberta, Edmonton, Alberta, Canada
| | - Peter E. Konrad
- Department of Neurosurgery, West Virginia University, Morgantown, West Virginia; and
- Integrative Neuroscience & Clinical Innovation, Rockefeller Neuroscience Institute, Morgantown, West Virginia
| | - Vivian K. Mushahwar
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
- Institute for Augmentative and Restorative Technologies and Health Innovations (iSMART), University of Alberta, Edmonton, Alberta, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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Spagnoli G, Parrella E, Ghazanfar Tehrani S, Mengoni F, Salari V, Nistreanu C, Scambi I, Sbarbati A, Bertini G, Fabene PF. Glial Response and Neuronal Modulation Induced by Epidural Electrode Implant in the Pilocarpine Mouse Model of Epilepsy. Biomolecules 2024; 14:834. [PMID: 39062548 PMCID: PMC11274793 DOI: 10.3390/biom14070834] [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: 05/01/2024] [Revised: 06/23/2024] [Accepted: 07/01/2024] [Indexed: 07/28/2024] Open
Abstract
In animal models of epilepsy, cranial surgery is often required to implant electrodes for electroencephalography (EEG) recording. However, electrode implants can lead to the activation of glial cells and interfere with physiological neuronal activity. In this study, we evaluated the impact of epidural electrode implants in the pilocarpine mouse model of temporal lobe epilepsy. Brain neuroinflammation was assessed 1 and 3 weeks after surgery by cytokines quantification, immunohistochemistry, and western blotting. Moreover, we investigated the effect of pilocarpine, administered two weeks after surgery, on mice mortality rate. The reported results indicate that implanted mice suffer from neuroinflammation, characterized by an early release of pro-inflammatory cytokines, microglia activation, and subsequent astrogliosis, which persists after three weeks. Notably, mice subjected to electrode implants displayed a higher mortality rate following pilocarpine injection 2 weeks after the surgery. Moreover, the analysis of EEGs recorded from implanted mice revealed a high number of single spikes, indicating a possible increased susceptibility to seizures. In conclusion, epidural electrode implant in mice promotes neuroinflammation that could lower the seizure thresholds to pilocarpine and increase the death rate. An improved protocol considering the persistent neuroinflammation induced by electrode implants will address refinement and reduction, two of the 3Rs principles for the ethical use of animals in scientific research.
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Affiliation(s)
- Giulia Spagnoli
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Edoardo Parrella
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
- Section of Innovation Biomedicine, Department of Engineering for Innovation Medicine, University of Verona, 37134 Verona, Italy;
| | - Sara Ghazanfar Tehrani
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Francesca Mengoni
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Valentina Salari
- Section of Innovation Biomedicine, Department of Engineering for Innovation Medicine, University of Verona, 37134 Verona, Italy;
| | - Cristina Nistreanu
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Ilaria Scambi
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Andrea Sbarbati
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Giuseppe Bertini
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
| | - Paolo Francesco Fabene
- Section of Anatomy and Histology, Department of Neurosciences, Biomedicine, and Movement Science, School of Medicine, University of Verona, 37124 Verona, Italy; (G.S.); (E.P.); (S.G.T.); (F.M.); (C.N.); (I.S.); (A.S.); (G.B.)
- Section of Innovation Biomedicine, Department of Engineering for Innovation Medicine, University of Verona, 37134 Verona, Italy;
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5
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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.
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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.
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6
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Wu B, Castagnola E, McClung CA, Cui XT. PEDOT/CNT Flexible MEAs Reveal New Insights into the Clock Gene's Role in Dopamine Dynamics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2308212. [PMID: 38430532 PMCID: PMC11251561 DOI: 10.1002/advs.202308212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/26/2024] [Indexed: 03/04/2024]
Abstract
Substantial evidence has shown that the Circadian Locomotor Output Cycles Kaput (Clock) gene is a core transcription factor of circadian rhythms that regulates dopamine (DA) synthesis. To shed light on the mechanism of this interaction, flexible multielectrode arrays (MEAs) are developed that can measure both DA concentrations and electrophysiology chronically. The dual functionality is enabled by conducting polymer PEDOT doped with acid-functionalized carbon nanotubes (CNT). The PEDOT/CNT microelectrode coating maintained stable electrochemical impedance and DA detection by square wave voltammetry for 4 weeks in vitro. When implanted in wild-type (WT) and Clock mutation (MU) mice, MEAs measured tonic DA concentration and extracellular neural activity with high spatial and temporal resolution for 4 weeks. A diurnal change of DA concentration in WT is observed, but not in MU, and a higher basal DA concentration and stronger cocaine-induced DA increase in MU. Meanwhile, striatal neuronal firing rate is found to be positively correlated with DA concentration in both animal groups. These findings offer new insights into DA dynamics in the context of circadian rhythm regulation, and the chronically reliable performance and dual measurement capability of this technology hold great potential for a broad range of neuroscience research.
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Affiliation(s)
- Bingchen Wu
- Department of BioengineeringUniversity of PittsburghPittsburghPA15213USA
- Center for the Neural Basis of CognitionPittsburghPA15213USA
| | - Elisa Castagnola
- Department of BioengineeringUniversity of PittsburghPittsburghPA15213USA
- Department of Biomedical EngineeringLouisiana Tech UniversityRustonLA71272USA
| | | | - Xinyan Tracy Cui
- Department of BioengineeringUniversity of PittsburghPittsburghPA15213USA
- Center for the Neural Basis of CognitionPittsburghPA15213USA
- McGowan Institute for Regenerative MedicinePittsburghPA15219USA
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7
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Li F, Gallego J, Tirko NN, Greaser J, Bashe D, Patel R, Shaker E, Van Valkenburg GE, Alsubhi AS, Wellman S, Singh V, Padilla CG, Gheres KW, Broussard JI, Bagwell R, Mulvihill M, Kozai TDY. Low-intensity pulsed ultrasound stimulation (LIPUS) modulates microglial activation following intracortical microelectrode implantation. Nat Commun 2024; 15:5512. [PMID: 38951525 PMCID: PMC11217463 DOI: 10.1038/s41467-024-49709-9] [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: 12/07/2023] [Accepted: 06/13/2024] [Indexed: 07/03/2024] Open
Abstract
Microglia are important players in surveillance and repair of the brain. Implanting an electrode into the cortex activates microglia, produces an inflammatory cascade, triggers the foreign body response, and opens the blood-brain barrier. These changes can impede intracortical brain-computer interfaces performance. Using two-photon imaging of implanted microelectrodes, we test the hypothesis that low-intensity pulsed ultrasound stimulation can reduce microglia-mediated neuroinflammation following the implantation of microelectrodes. In the first week of treatment, we found that low-intensity pulsed ultrasound stimulation increased microglia migration speed by 128%, enhanced microglia expansion area by 109%, and a reduction in microglial activation by 17%, indicating improved tissue healing and surveillance. Microglial coverage of the microelectrode was reduced by 50% and astrocytic scarring by 36% resulting in an increase in recording performance at chronic time. The data indicate that low-intensity pulsed ultrasound stimulation helps reduce the foreign body response around chronic intracortical microelectrodes.
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Affiliation(s)
- Fan Li
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neural Basis of Cognition, Pittsburgh, PA, USA
- Computational Modeling and Simulation PhD Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jazlyn Gallego
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Natasha N Tirko
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | | | - Derek Bashe
- Washington University in St. Louis, St. Louis, MO, USA
| | - Rudra Patel
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
| | - Eric Shaker
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | | | | | | | - Vanshika Singh
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Camila Garcia Padilla
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neural Basis of Cognition, Pittsburgh, PA, USA
| | | | | | | | | | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for Neural Basis of Cognition, Pittsburgh, PA, USA.
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA.
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA.
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8
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Shi D, Narayanan S, Woeppel K, Cui XT. Improving the Biocompatibility and Functionality of Neural Interface Devices with Silica Nanoparticles. Acc Chem Res 2024; 57:1684-1695. [PMID: 38814586 PMCID: PMC11191400 DOI: 10.1021/acs.accounts.4c00160] [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: 03/10/2024] [Revised: 05/03/2024] [Accepted: 05/17/2024] [Indexed: 05/31/2024]
Abstract
ConspectusNeural interface technologies enable bidirectional communication between the nervous system and external instrumentation. Advancements in neural interface devices not only open new frontiers for neuroscience research, but also hold great promise for clinical diagnosis, therapy, and rehabilitation for various neurological disorders. However, the performance of current neural electrode devices, often termed neural probes, is far from satisfactory. Glial scarring, neuronal degeneration, and electrode degradation eventually cause the devices to lose their connection with the brain. To improve the chronic performance of neural probes, efforts need to be made on two fronts: enhancing the physiochemical properties of the electrode materials and mitigating the undesired host tissue response.In this Account, we discuss our efforts in developing silica-nanoparticle-based (SiNP) coatings aimed at enhancing neural probe electrochemical properties and promoting device-tissue integration. Our work focuses on three approaches:(1) SiNPs' surface texturization to enhance biomimetic protein coatings for promoting neural integration. Through covalent immobilization, SiNP introduces biologically relevant nanotopography to neural probe surfaces, enhancing neuronal cell attachments and inhibiting microglia. The SiNP base coating further increases the binding density and stability of bioactive molecules such as L1CAM and facilitates the widespread dissemination of biomimetic coatings. (2) Doping SiNPs into conductive polymer electrode coatings improves the electrochemical properties and stability. As neural interface devices are moving to subcellular sizes to escape the immune response and high electrode site density to increase spatial resolution, the electrode sites need to be very small. The smaller electrode size comes at the cost of a high electrode impedance, elevated thermal noise, and insufficient charge injection capacity. Electrochemically deposited conductive polymer films reduce electrode impedance but do not endure prolonged electrical cycling. When incorporated into conductive polymer coatings as a dopant, the SiNP provides structural support for the polymer thin films, significantly increasing their stability and durability. Low interfacial impedance maintained by the conducting polymer/SiNP composite is critical for extended electrode longevity and effective charge injection in chronic neural stimulation applications. (3) Porous nanoparticles are used as drug carriers in conductive polymer coatings for local drug/neurochemical delivery. When triggered by external electrical stimuli, drug molecules and neurochemicals can be released in a controlled manner. Such precise focal manipulation of cellular and vascular behavior enables us to probe brain circuitry and develop therapeutic applications.We foresee tremendous opportunities for further advancing the functionality of SiNP coatings by incorporating new nanoscale components and integrating the coating with other design strategies. With an enriched nanoscale toolbox and optimized design strategies, we can create customizable multifunctional and multimodal neural interfaces that can operate at multiple spatial levels and seamlessly integrate with the host tissue for extended applications.
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Affiliation(s)
- Delin Shi
- University
of Pittsburgh, Department of Bioengineering, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
- Center
for the Neural Basis of Cognition, 4400 Fifth Avenue, Suite 115, Pittsburgh, Pennsylvania 15213, United States
| | - Sharada Narayanan
- University
of Pittsburgh, Department of Bioengineering, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
- Center
for the Neural Basis of Cognition, 4400 Fifth Avenue, Suite 115, Pittsburgh, Pennsylvania 15213, United States
| | - Kevin Woeppel
- University
of Pittsburgh, Department of Bioengineering, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
- Center
for the Neural Basis of Cognition, 4400 Fifth Avenue, Suite 115, Pittsburgh, Pennsylvania 15213, United States
| | - Xinyan Tracy Cui
- University
of Pittsburgh, Department of Bioengineering, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
- Center
for the Neural Basis of Cognition, 4400 Fifth Avenue, Suite 115, Pittsburgh, Pennsylvania 15213, United States
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9
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Wellman S, Forrest AM, Douglas MM, Subbaraman A, Zhang G, Kozai TDY. Dynamic changes in structure and function of brain mural cells around chronically implanted microelectrodes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.11.598494. [PMID: 38915601 PMCID: PMC11195141 DOI: 10.1101/2024.06.11.598494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Integration of neural interfaces with minimal tissue disruption in the brain is ideal to develop robust tools that can address essential neuroscience questions and combat neurological disorders. However, implantation of intracortical devices provokes severe tissue inflammation within the brain, which requires a high metabolic demand to support a complex series of cellular events mediating tissue degeneration and wound healing. Pericytes, peri-vascular cells involved in blood-brain barrier maintenance, vascular permeability, waste clearance, and angiogenesis, have recently been implicated as potential perpetuators of neurodegeneration in brain injury and disease. While the intimate relationship between pericytes and the cortical microvasculature have been explored in other disease states, their behavior following microelectrode implantation, which is responsible for direct blood vessel disruption and dysfunction, is currently unknown. Using two-photon microscopy we observed dynamic changes in the structure and function of pericytes during implantation of a microelectrode array over a 4-week implantation period. Pericytes respond to electrode insertion through transient increases in intracellular calcium and underlying constriction of capillary vessels. Within days following the initial insertion, we observed an influx of new, proliferating pericytes which contribute to new blood vessel formation. Additionally, we discovered a potentially novel population of reactive immune cells in close proximity to the electrode-tissue interface actively engaging in encapsulation of the microelectrode array. Finally, we determined that intracellular pericyte calcium can be modulated by intracortical microstimulation in an amplitude- and frequency-dependent manner. This study provides a new perspective on the complex biological sequelae occurring the electrode-tissue interface and will foster new avenues of potential research consideration and lead to development of more advanced therapeutic interventions towards improving the biocompatibility of neural electrode technology.
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10
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Dhawan V, Martin PN, Hu X, Cui XT. Investigation of a chondroitin sulfate-based bioactive coating for neural interface applications. J Mater Chem B 2024; 12:5535-5550. [PMID: 38747002 PMCID: PMC11152038 DOI: 10.1039/d4tb00501e] [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: 03/08/2024] [Accepted: 05/09/2024] [Indexed: 06/06/2024]
Abstract
Invasive neural implants allow for high-resolution bidirectional communication with the nervous tissue and have demonstrated the ability to record neural activity, stimulate neurons, and sense neurochemical species with high spatial selectivity and resolution. However, upon implantation, they are exposed to a foreign body response which can disrupt the seamless integration of the device with the native tissue and lead to deterioration in device functionality for chronic implantation. Modifying the device surface by incorporating bioactive coatings has been a promising approach to camouflage the device and improve integration while maintaining device performance. In this work, we explored the novel application of a chondroitin sulfate (CS) based hydrophilic coating, with anti-fouling and neurite-growth promoting properties for neural recording electrodes. CS-coated samples exhibited significantly reduced protein-fouling in vitro which was maintained for up to 4-weeks. Cell culture studies revealed a significant increase in neurite attachment and outgrowth and a significant decrease in microglia attachment and activation for the CS group as compared to the control. After 1-week of in vivo implantation in the mouse cortex, the coated probes demonstrated significantly lower biofouling as compared to uncoated controls. Like the in vitro results, increased neuronal population (neuronal nuclei and neurofilament) and decreased microglial activation were observed. To assess the coating's effect on the recording performance of silicon microelectrodes, we implanted coated and uncoated electrodes in the mouse striatum for 1 week and performed impedance and recording measurements. We observed significantly lower impedance in the coated group, likely due to the increased wettability of the coated surface. The peak-to-peak amplitude and the noise floor levels were both lower in the CS group compared to the controls, which led to a comparable signal-to-noise ratio between the two groups. The overall single unit yield (% channels recording a single unit) was 74% for the CS and 67% for the control group on day 1. Taken together, this study demonstrates the effectiveness of the polysaccharide-based coating in reducing biofouling and improving biocompatibility for neural electrode devices.
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Affiliation(s)
- Vaishnavi Dhawan
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Paige Nicole Martin
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Xiaoming Hu
- Department of Neurology, University of Pittsburgh, PA, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for Neural Basis of Cognition, Pittsburgh, PA, USA
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11
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Yang Q, Vazquez AL, Cui XT. Revealing in vivo cellular mechanisms of cerebral microbleeds on neurons and microglia across cortical layers. iScience 2024; 27:109371. [PMID: 38510113 PMCID: PMC10951986 DOI: 10.1016/j.isci.2024.109371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/28/2023] [Accepted: 02/26/2024] [Indexed: 03/22/2024] Open
Abstract
Cerebral microbleeds (CMBs) are associated with higher risk for various neurological diseases including stroke, dementia, and Alzheimer's disease. However, the understanding of cellular pathology of CMBs, particularly in deep brain regions, remains limited. Utilizing two-photon microscopy and microprism implantation, we longitudinally imaged the impact of CMBs on neuronal and microglial activities across cortical depths in awake mice. A temporary decline in spontaneous neuronal activity occurred throughout cortical layers, followed by recovery within a week. However, significant changes of neuron-neuron activity correlations persisted for weeks. Moreover, microglial contact with neuron soma significantly increased post-microbleeds, indicating an important modulatory role of microglia. Notably, microglial contact, negatively correlated with neuronal firing rate in normal conditions, became uncorrelated after microbleeds, suggesting a decreased neuron-microglia inhibition. These findings reveal chronic alterations in cortical neuronal networks and microglial-neuronal interactions across cortical depths, shedding light on the pathology of CMBs.
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Affiliation(s)
- Qianru Yang
- Department of Neurosurgery, Stanford University, Palo Alto, CA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
| | - Alberto L. Vazquez
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - X. Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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12
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McNamara IN, Wellman SM, Li L, Eles JR, Savya S, Sohal HS, Angle MR, Kozai TDY. Electrode sharpness and insertion speed reduce tissue damage near high-density penetrating arrays. J Neural Eng 2024; 21:026030. [PMID: 38518365 DOI: 10.1088/1741-2552/ad36e1] [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: 11/22/2023] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
Objective. Over the past decade, neural electrodes have played a crucial role in bridging biological tissues with electronic and robotic devices. This study focuses on evaluating the optimal tip profile and insertion speed for effectively implanting Paradromics' high-density fine microwire arrays (FμA) prototypes into the primary visual cortex (V1) of mice and rats, addressing the challenges associated with the 'bed-of-nails' effect and tissue dimpling.Approach. Tissue response was assessed by investigating the impact of electrodes on the blood-brain barrier (BBB) and cellular damage, with a specific emphasis on tailored insertion strategies to minimize tissue disruption during electrode implantation.Main results.Electro-sharpened arrays demonstrated a marked reduction in cellular damage within 50μm of the electrode tip compared to blunt and angled arrays. Histological analysis revealed that slow insertion speeds led to greater BBB compromise than fast and pneumatic methods. Successful single-unit recordings validated the efficacy of the optimized electro-sharpened arrays in capturing neural activity.Significance.These findings underscore the critical role of tailored insertion strategies in minimizing tissue damage during electrode implantation, highlighting the suitability of electro-sharpened arrays for long-term implant applications. This research contributes to a deeper understanding of the complexities associated with high-channel-count microelectrode array implantation, emphasizing the importance of meticulous assessment and optimization of key parameters for effective integration and minimal tissue disruption. By elucidating the interplay between insertion parameters and tissue response, our study lays a strong foundation for the development of advanced implantable devices with a reduction in reactive gliosis and improved performance in neural recording applications.
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Affiliation(s)
- Ingrid N McNamara
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Lehong Li
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Sajishnu Savya
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | | | | | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center of the Basis of Neural Cognition, Pittsburgh, PA, United States of America
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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13
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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.
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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
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14
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Schlotterose L, Cossais F, Lucius R, Hattermann K. Resveratrol Alleviates the Early Challenges of Implant-Based Drug Delivery in a Human Glial Cell Model. Int J Mol Sci 2024; 25:2078. [PMID: 38396755 PMCID: PMC10889494 DOI: 10.3390/ijms25042078] [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: 01/18/2024] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Brain diseases are oftentimes life-threatening and difficult to treat. The local administration of drug substances using brain implants can increase on-site concentrations and decrease systemic side effects. However, the biocompatibility of potential brain implant materials needs to be evaluated carefully as implants can trigger foreign body reactions, particularly by increasing the microglia and astrocyte reactivity. To date, these tests have been frequently conducted in very simple in vitro models, in particular not respecting the key players in glial cell reactions and the challenges of surgical implantation characterized by the disruption of oxygen and nutrient supply. Thus, we established an in vitro model in which we treated human glial cell lines with reduced oxygen and glucose levels. The model displayed cytokine and reactive oxygen species release from reactive microglia and an increase in a marker of reactive astrocytes, galectin-3. Moreover, the treatment caused changes in the cell survival and triggered the production of hypoxia-inducible factor 1α. In this comprehensive platform, we demonstrated the protective effect of the natural polyphenol resveratrol as a model substance, which might be included in brain implants to ease the undesired glial cell response. Overall, a glial-cell-based in vitro model of the initial challenges of local brain disease treatment may prove useful for investigating new therapy options.
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Affiliation(s)
| | | | | | - Kirsten Hattermann
- Institute of Anatomy, Kiel University, 24118 Kiel, Germany; (L.S.); (R.L.)
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15
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Mousavi H, Dauly G, Dieuset G, El Merhie A, Ismailova E, Wendling F, Al Harrach M. Tuning Microelectrodes' Impedance to Improve Fast Ripples Recording. Bioengineering (Basel) 2024; 11:102. [PMID: 38275582 PMCID: PMC11154299 DOI: 10.3390/bioengineering11010102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/11/2024] [Accepted: 01/19/2024] [Indexed: 01/27/2024] Open
Abstract
Epilepsy is a chronic neurological disorder characterized by recurrent seizures resulting from abnormal neuronal hyperexcitability. In the case of pharmacoresistant epilepsy requiring resection surgery, the identification of the Epileptogenic Zone (EZ) is critical. Fast Ripples (FRs; 200-600 Hz) are one of the promising biomarkers that can aid in EZ delineation. However, recording FRs requires physically small electrodes. These microelectrodes suffer from high impedance, which significantly impacts FRs' observability and detection. In this study, we investigated the potential of a conductive polymer coating to enhance FR observability. We employed biophysical modeling to compare two types of microelectrodes: Gold (Au) and Au coated with the conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (Au/PEDOT:PSS). These electrodes were then implanted into the CA1 hippocampal neural network of epileptic mice to record FRs during epileptogenesis. The results showed that the polymer-coated electrodes had a two-order lower impedance as well as a higher transfer function amplitude and cut-off frequency. Consequently, FRs recorded with the PEDOT:PSS-coated microelectrode yielded significantly higher signal energy compared to the uncoated one. The PEDOT:PSS coating improved the observability of the recorded FRs and thus their detection. This work paves the way for the development of signal-specific microelectrode designs that allow for better targeting of pathological biomarkers.
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Affiliation(s)
- Hajar Mousavi
- Bioelectronics Department, Ecoles des Mines de Saint Etienne, CMP-EMSE, MOC, 13541 Gardanne, France; (H.M.); (A.E.M.); (E.I.)
| | - Gautier Dauly
- INSERM, LTSI-U1099, University of Rennes, 35000 Rennes, France; (G.D.); (G.D.); (F.W.)
| | - Gabriel Dieuset
- INSERM, LTSI-U1099, University of Rennes, 35000 Rennes, France; (G.D.); (G.D.); (F.W.)
| | - Amira El Merhie
- Bioelectronics Department, Ecoles des Mines de Saint Etienne, CMP-EMSE, MOC, 13541 Gardanne, France; (H.M.); (A.E.M.); (E.I.)
- Laboratoire Matière et Systèmes Complexes, Université Paris Cité, CNRS UMR 7057, 10 Rue Alice Domon et Léonie Duquet, 75013 Paris, France
| | - Esma Ismailova
- Bioelectronics Department, Ecoles des Mines de Saint Etienne, CMP-EMSE, MOC, 13541 Gardanne, France; (H.M.); (A.E.M.); (E.I.)
| | - Fabrice Wendling
- INSERM, LTSI-U1099, University of Rennes, 35000 Rennes, France; (G.D.); (G.D.); (F.W.)
| | - Mariam Al Harrach
- INSERM, LTSI-U1099, University of Rennes, 35000 Rennes, France; (G.D.); (G.D.); (F.W.)
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16
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Miziev S, Pawlak WA, Howard N. Comparative analysis of energy transfer mechanisms for neural implants. Front Neurosci 2024; 17:1320441. [PMID: 38292898 PMCID: PMC10825050 DOI: 10.3389/fnins.2023.1320441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 12/19/2023] [Indexed: 02/01/2024] Open
Abstract
As neural implant technologies advance rapidly, a nuanced understanding of their powering mechanisms becomes indispensable, especially given the long-term biocompatibility risks like oxidative stress and inflammation, which can be aggravated by recurrent surgeries, including battery replacements. This review delves into a comprehensive analysis, starting with biocompatibility considerations for both energy storage units and transfer methods. The review focuses on four main mechanisms for powering neural implants: Electromagnetic, Acoustic, Optical, and Direct Connection to the Body. Among these, Electromagnetic Methods include techniques such as Near-Field Communication (RF). Acoustic methods using high-frequency ultrasound offer advantages in power transmission efficiency and multi-node interrogation capabilities. Optical methods, although still in early development, show promising energy transmission efficiencies using Near-Infrared (NIR) light while avoiding electromagnetic interference. Direct connections, while efficient, pose substantial safety risks, including infection and micromotion disturbances within neural tissue. The review employs key metrics such as specific absorption rate (SAR) and energy transfer efficiency for a nuanced evaluation of these methods. It also discusses recent innovations like the Sectored-Multi Ring Ultrasonic Transducer (S-MRUT), Stentrode, and Neural Dust. Ultimately, this review aims to help researchers, clinicians, and engineers better understand the challenges of and potentially create new solutions for powering neural implants.
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17
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Krishnan J, Joseph R, Vayalappil MC, Krishnan S, Kishore A. A Review on Implantable Neuroelectrodes. Crit Rev Biomed Eng 2024; 52:21-39. [PMID: 37938182 DOI: 10.1615/critrevbiomedeng.2023049282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
The efficacy of every neuromodulation modality depends upon the characteristics of the electrodes used to stimulate the chosen target. The geometrical, chemical, mechanical and physical configuration of electrodes used in neurostimulation affects several performance attributes like stimulation efficiency, selectivity, tissue response, etc. The efficiency of stimulation in relation to electrode impedance is influenced by the electrode material and/or its geometry. The nature of the electrode material determines the charge transfer across the electrode-tissue interface, which also relates to neuronal tissue damage. Electrode morphology or configuration pattern can facilitate the modulation of extracellular electric field (field shaping). This enables selective activation of neurons and minimizes side effects. Biocompatibility and biostability of the electrode materials or electrode coating have a role in glial formation and tissue damage. Mechanical and electrochemical stability (corrosion resistance) determines the long-term efficacy of any neuromodulation technique. Here, a review of electrodes typically used for implantable neuromodulation is discussed. Factors affecting the performance of electrodes like stimulation efficiency, selectivity and tissue responses to the electrode-tissue interface are discussed. Technological advancements to improve electrode characteristics are also included.
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Affiliation(s)
- Jithin Krishnan
- Department of Medical Devices Engineering, BMT Wing, SCTIMST, Kerala, India
| | - Roy Joseph
- Department of Medical Devices Engineering, BMT Wing, SCTIMST, Kerala, India
| | | | | | - Asha Kishore
- Aster Parkinson & Movement Disorder Centre, Senior Consultant Neurologist and Movement Disorder Specialist
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18
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Woeppel KM, Krahe DD, Robbins EM, Vazquez AL, Cui XT. Electrically Controlled Vasodilator Delivery from PEDOT/Silica Nanoparticle Modulates Vessel Diameter in Mouse Brain. Adv Healthc Mater 2024; 13:e2301221. [PMID: 37916912 PMCID: PMC10842908 DOI: 10.1002/adhm.202301221] [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: 04/18/2023] [Revised: 10/16/2023] [Indexed: 11/03/2023]
Abstract
Vascular damage and reduced tissue perfusion are expected to majorly contribute to the loss of neurons or neural signals around implanted electrodes. However, there are limited methods of controlling the vascular dynamics in tissues surrounding these implants. This work utilizes conducting polymer poly(ethylenedioxythiophene) and sulfonated silica nanoparticle composite (PEDOT/SNP) to load and release a vasodilator, sodium nitroprusside, to controllably dilate the vasculature around carbon fiber electrodes (CFEs) implanted in the mouse cortex. The vasodilator release is triggered via electrical stimulation and the amount of release increases with increasing electrical pulses. The vascular dynamics are monitored in real-time using two-photon microscopy, with changes in vessel diameters quantified before, during, and after the release of the vasodilator into the tissues. This work observes significant increases in vessel diameters when the vasodilator is electrically triggered to release, and differential effects of the drug release on vessels of different sizes. In conclusion, the use of nanoparticle reservoirs in conducting polymer-based drug delivery platforms enables the controlled delivery of vasodilator into the implant environment, effectively altering the local vascular dynamics on demand. With further optimization, this technology could be a powerful tool to improve the neural electrode-tissue interface and study neurovascular coupling.
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Affiliation(s)
- Kevin M Woeppel
- Department of Bioengineering, University of Pittsburgh, United States
| | - Daniela D Krahe
- Department of Bioengineering, University of Pittsburgh, United States
| | - Elaine M Robbins
- Department of Bioengineering, University of Pittsburgh, United States
| | - Alberto L Vazquez
- Department of Bioengineering, University of Pittsburgh, United States
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, United States
- Department of Radiology, University of Pittsburgh, United States
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, United States
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, United States
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, United States
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Jiao Y, Lei M, Zhu J, Chang R, Qu X. Advances in electrode interface materials and modification technologies for brain-computer interfaces. BIOMATERIALS TRANSLATIONAL 2023; 4:213-233. [PMID: 38282708 PMCID: PMC10817795 DOI: 10.12336/biomatertransl.2023.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 11/13/2023] [Accepted: 11/24/2023] [Indexed: 01/30/2024]
Abstract
Recent advances in neuroelectrode interface materials and modification technologies are reviewed. Brain-computer interface is the new method of human-computer interaction, which not only can realise the exchange of information between the human brain and external devices, but also provides a brand-new means for the diagnosis and treatment of brain-related diseases. The neural electrode interface part of brain-computer interface is an important area for electrical, optical and chemical signal transmission between brain tissue system and external electronic devices, which determines the performance of brain-computer interface. In order to solve the problems of insufficient flexibility, insufficient signal recognition ability and insufficient biocompatibility of traditional rigid electrodes, researchers have carried out extensive studies on the neuroelectrode interface in terms of materials and modification techniques. This paper introduces the biological reactions that occur in neuroelectrodes after implantation into brain tissue and the decisive role of the electrode interface for electrode function. Following this, the latest research progress on neuroelectrode materials and interface materials is reviewed from the aspects of neuroelectrode materials and modification technologies, firstly taking materials as a clue, and then focusing on the preparation process of neuroelectrode coatings and the design scheme of functionalised structures.
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Affiliation(s)
- Yunke Jiao
- Key Laboratory for Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai, China
| | - Miao Lei
- Key Laboratory for Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai, China
| | - Jianwei Zhu
- Key Laboratory for Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai, China
| | - Ronghang Chang
- Key Laboratory for Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai, China
| | - Xue Qu
- Key Laboratory for Ultrafine Materials of Ministry of Education, School of Material Science and Engineering, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai, China
- Wenzhou Institute of Shanghai University, Wenzhou, Zhejiang Province, China
- Shanghai Frontier Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai, China
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Ferreira-Fernandes E, Laranjo M, Reis T, Canijo B, Ferreira PA, Martins P, Vilarinho J, Tavakoli M, Kunicki C, Peça J. In vivo recordings in freely behaving mice using independent silicon probes targeting multiple brain regions. Front Neural Circuits 2023; 17:1293620. [PMID: 38186631 PMCID: PMC10771849 DOI: 10.3389/fncir.2023.1293620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 12/05/2023] [Indexed: 01/09/2024] Open
Abstract
In vivo recordings in freely behaving animals are crucial to understand the neuronal circuit basis of behavior. Although current multi-channel silicon probes provide unparalleled sampling density, the study of interacting neuronal populations requires the implantation of multiple probes across different regions of the brain. Ideally, these probes should be independently adjustable, to maximize the yield, and recoverable, to mitigate costs. In this work, we describe the implementation of a miniaturized 3D-printed headgear system for chronic in vivo recordings in mice using independently movable silicon probes targeting multiple brain regions. We successfully demonstrated the performance of the headgear by simultaneously recording the neuronal activity in the prelimbic cortex and dorsal hippocampus. The system proved to be sturdy, ensuring high-quality stable recordings and permitted reuse of the silicon probes, with no observable interference in mouse innate behaviors.
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Affiliation(s)
- Emanuel Ferreira-Fernandes
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
| | - Mariana Laranjo
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
- PhD Program in Experimental Biology and Biomedicine (PDBEB), University of Coimbra, Coimbra, Portugal
| | - Tiago Reis
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
- PhD Program in Experimental Biology and Biomedicine (PDBEB), University of Coimbra, Coimbra, Portugal
| | - Bárbara Canijo
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Pedro A. Ferreira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Pedro Martins
- Department of Architecture, University of Coimbra, Coimbra, Portugal
| | - João Vilarinho
- Institute of Systems and Robotics, Department of Electrical and Computer Engineering, University of Coimbra, Coimbra, Portugal
| | - Mahmoud Tavakoli
- Institute of Systems and Robotics, Department of Electrical and Computer Engineering, University of Coimbra, Coimbra, Portugal
| | - Carolina Kunicki
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Vasco da Gama Research Center (CIVG), Vasco da Gama University School (EUVG), Coimbra, Portugal
| | - João Peça
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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Boulingre M, Portillo-Lara R, Green RA. Biohybrid neural interfaces: improving the biological integration of neural implants. Chem Commun (Camb) 2023; 59:14745-14758. [PMID: 37991846 PMCID: PMC10720954 DOI: 10.1039/d3cc05006h] [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: 10/11/2023] [Accepted: 11/10/2023] [Indexed: 11/24/2023]
Abstract
Implantable neural interfaces (NIs) have emerged in the clinic as outstanding tools for the management of a variety of neurological conditions caused by trauma or disease. However, the foreign body reaction triggered upon implantation remains one of the major challenges hindering the safety and longevity of NIs. The integration of tools and principles from biomaterial design and tissue engineering has been investigated as a promising strategy to develop NIs with enhanced functionality and performance. In this Feature Article, we highlight the main bioengineering approaches for the development of biohybrid NIs with an emphasis on relevant device design criteria. Technical and scientific challenges associated with the fabrication and functional assessment of technologies composed of both artificial and biological components are discussed. Lastly, we provide future perspectives related to engineering, regulatory, and neuroethical challenges to be addressed towards the realisation of the promise of biohybrid neurotechnology.
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Affiliation(s)
- Marjolaine Boulingre
- Department of Bioengineering, Imperial College London, South Kensington, London, SW7 2AZ, UK
| | - Roberto Portillo-Lara
- 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
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22
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Li F, Gallego J, Tirko NN, Greaser J, Bashe D, Patel R, Shaker E, Van Valkenburg GE, Alsubhi AS, Wellman S, Singh V, Padill CG, Gheres KW, Bagwell R, Mulvihill M, Kozai TDY. Low-intensity pulsed ultrasound stimulation (LIPUS) modulates microglial activation following intracortical microelectrode implantation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570162. [PMID: 38105969 PMCID: PMC10723293 DOI: 10.1101/2023.12.05.570162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Microglia are important players in surveillance and repair of the brain. Their activation mediates neuroinflammation caused by intracortical microelectrode implantation, which impedes the application of intracortical brain-computer interfaces (BCIs). While low-intensity pulsed ultrasound stimulation (LIPUS) can attenuate microglial activation, its potential to modulate the microglia-mediated neuroinflammation and enhance the bio-integration of microelectrodes remains insufficiently explored. We found that LIPUS increased microglia migration speed from 0.59±0.04 to 1.35±0.07 µm/hr on day 1 and enhanced microglia expansion area from 44.50±6.86 to 93.15±8.77 µm 2 /min on day 7, indicating improved tissue healing and surveillance. Furthermore, LIPUS reduced microglial activation by 17% on day 6, vessel-associated microglia ratio from 70.67±6.15 to 40.43±3.87% on day 7, and vessel diameter by 20% on day 28. Additionally, microglial coverage of the microelectrode was reduced by 50% in week 1, indicating better tissue-microelectrode integration. These data reveal that LIPUS helps resolve neuroinflammation around chronic intracortical microelectrodes.
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Sanda R, Yamashita K, Sawahata H, Sakamoto K, Yamagiwa S, Yokoyama S, Numano R, Koida K, Kawano T. Low-invasive neural recording in mouse models with diabetes via an ultrasmall needle-electrode. Biosens Bioelectron 2023; 240:115605. [PMID: 37669586 DOI: 10.1016/j.bios.2023.115605] [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: 04/14/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 09/07/2023]
Abstract
Diabetes is known to cause a variety of complications, having a high correlation with Alzheimer's disease. Electrophysiological recording using a microscale needle electrode is a promising technology for the study, however, diabetic brain tissue is more difficult to record neuronal activities than normal tissue due to these complications including the development of cerebrovascular disease. Here we show an electrophysiological methodology for diabetic db/db mice (+Leprdb/+Leprdb) using a 4-μm-tip diameter needle-electrode device. The needle electrode minimized the tissue injury when compared to a typical larger metal electrode, as confirmed by bleeding during penetration. The proposed electrode device showed both acute and chronic in vivo recording capabilities for diabetic mice while reducing the glial cells' responses. Because of these device characteristics, the 4-μm-tip diameter needle-electrode will allow electrophysiological studies on diabetes models of not only mice, as proven in this study, but also other animals.
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Affiliation(s)
- Rioki Sanda
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan
| | - Koji Yamashita
- Electronics-Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan
| | - Hirohito Sawahata
- National Institute of Technology, Ibaraki College, 866 Nakane, Hitachinaka, 312-8508, Japan
| | - Kensei Sakamoto
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan
| | - Shota Yamagiwa
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan
| | - Shohei Yokoyama
- TechnoPro, Inc., TechnoPro R&D Company, 6-10-1 Roppongi, Minato-ku, 106-6135, Japan
| | - Rika Numano
- Electronics-Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan; Department of Applied Chemistry and Life Science, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan
| | - Kowa Koida
- Electronics-Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan; Department of Computer Science and Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan
| | - Takeshi Kawano
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan; Electronics-Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku-cho, Toyohashi, 441-8580, Japan.
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24
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Chen K, Forrest A, Gonzalez Burgos G, Kozai TDY. Neuronal functional connectivity is impaired in a layer dependent manner near the chronically implanted microelectrodes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.06.565852. [PMID: 37986883 PMCID: PMC10659303 DOI: 10.1101/2023.11.06.565852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Objective This study aims to reveal longitudinal changes in functional network connectivity within and across different brain structures near the chronically implanted microelectrode. While it is well established that the foreign-body response (FBR) contributes to the gradual decline of the signals recorded from brain implants over time, how does the FBR impact affect the functional stability of neural circuits near implanted Brain-Computer Interfaces (BCIs) remains unknown. This research aims to illuminate how the chronic FBR can alter local neural circuit function and the implications for BCI decoders. Approach This study utilized multisite Michigan-style microelectrodes that span all cortical layers and the hippocampal CA1 region to collect spontaneous and visually-evoked electrophysiological activity. Alterations in neuronal activity near the microelectrode were tested assessing cross-frequency synchronization of LFP and spike entrainment to LFP oscillatory activity throughout 16 weeks after microelectrode implantation. Main Results The study found that cortical layer 4, the input-receiving layer, maintained activity over the implantation time. However, layers 2/3 rapidly experienced severe impairment, leading to a loss of proper intralaminar connectivity in the downstream output layers 5/6. Furthermore, the impairment of interlaminar connectivity near the microelectrode was unidirectional, showing decreased connectivity from Layers 2/3 to Layers 5/6 but not the reverse direction. In the hippocampus, CA1 neurons gradually became unable to properly entrain to the surrounding LFP oscillations. Significance This study provides a detailed characterization of network connectivity dysfunction over long-term microelectrode implantation periods. This new knowledge could contribute to the development of targeted therapeutic strategies aimed at improving the health of the tissue surrounding brain implants and potentially inform engineering of adaptive decoders as the FBR progresses. Our study's understanding of the dynamic changes in the functional network over time opens the door to developing interventions for improving the long-term stability and performance of intracortical microelectrodes.
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25
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Chen K, Garcia Padilla C, Kiselyov K, Kozai TDY. Cell-specific alterations in autophagy-lysosomal activity near the chronically implanted microelectrodes. Biomaterials 2023; 302:122316. [PMID: 37738741 PMCID: PMC10897938 DOI: 10.1016/j.biomaterials.2023.122316] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 08/22/2023] [Accepted: 09/02/2023] [Indexed: 09/24/2023]
Abstract
Intracortical microelectrodes that can record and stimulate brain activity have become a valuable technique for basic science research and clinical applications. However, long-term implantation of these microelectrodes can lead to progressive neurodegeneration in the surrounding microenvironment, characterized by elevation in disease-associated markers. Dysregulation of autophagy-lysosomal degradation, a major intracellular waste removal process, is considered a key factor in the onset and progression of neurodegenerative diseases. It is plausible that similar dysfunctions in autophagy-lysosomal degradation contribute to tissue degeneration following implantation-induced focal brain injury, ultimately impacting recording performance. To understand how the focal, persistent brain injury caused by long-term microelectrode implantation impairs autophagy-lysosomal pathway, we employed two-photon microscopy and immunohistology. This investigation focused on the spatiotemporal characterization of autophagy-lysosomal activity near the chronically implanted microelectrode. We observed an aberrant accumulation of immature autophagy vesicles near the microelectrode over the chronic implantation period. Additionally, we found deficits in autophagy-lysosomal clearance proximal to the chronic implant, which was associated with an accumulation of autophagy cargo and a reduction in lysosomal protease level during the chronic period. Furthermore, our evidence demonstrates reactive astrocytes have myelin-containing lysosomes near the microelectrode, suggesting its role of myelin engulfment during acute implantation period. Together, this study sheds light on the process of brain tissue degeneration caused by long-term microelectrode implantation, with a specific focus on impaired intracellular waste degradation.
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Affiliation(s)
- Keying Chen
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Camila Garcia Padilla
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Kirill Kiselyov
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA.
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26
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Perna A, Angotzi GN, Berdondini L, Ribeiro JF. Advancing the interfacing performances of chronically implantable neural probes in the era of CMOS neuroelectronics. Front Neurosci 2023; 17:1275908. [PMID: 38027514 PMCID: PMC10644322 DOI: 10.3389/fnins.2023.1275908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 10/10/2023] [Indexed: 12/01/2023] Open
Abstract
Tissue penetrating microelectrode neural probes can record electrophysiological brain signals at resolutions down to single neurons, making them invaluable tools for neuroscience research and Brain-Computer-Interfaces (BCIs). The known gradual decrease of their electrical interfacing performances in chronic settings, however, remains a major challenge. A key factor leading to such decay is Foreign Body Reaction (FBR), which is the cascade of biological responses that occurs in the brain in the presence of a tissue damaging artificial device. Interestingly, the recent adoption of Complementary Metal Oxide Semiconductor (CMOS) technology to realize implantable neural probes capable of monitoring hundreds to thousands of neurons simultaneously, may open new opportunities to face the FBR challenge. Indeed, this shift from passive Micro Electro-Mechanical Systems (MEMS) to active CMOS neural probe technologies creates important, yet unexplored, opportunities to tune probe features such as the mechanical properties of the probe, its layout, size, and surface physicochemical properties, to minimize tissue damage and consequently FBR. Here, we will first review relevant literature on FBR to provide a better understanding of the processes and sources underlying this tissue response. Methods to assess FBR will be described, including conventional approaches based on the imaging of biomarkers, and more recent transcriptomics technologies. Then, we will consider emerging opportunities offered by the features of CMOS probes. Finally, we will describe a prototypical neural probe that may meet the needs for advancing clinical BCIs, and we propose axial insertion force as a potential metric to assess the influence of probe features on acute tissue damage and to control the implantation procedure to minimize iatrogenic injury and subsequent FBR.
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Affiliation(s)
- Alberto Perna
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
- The Open University Affiliated Research Centre at Istituto Italiano di Tecnologia (ARC@IIT), Istituto Italiano di Tecnologia, Genova, Italy
| | - Gian Nicola Angotzi
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
| | - Luca Berdondini
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
| | - João Filipe Ribeiro
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
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Yan T, Suzuki K, Kameda S, Maeda M, Mihara T, Hirata M. Chronic subdural electrocorticography in nonhuman primates by an implantable wireless device for brain-machine interfaces. Front Neurosci 2023; 17:1260675. [PMID: 37841689 PMCID: PMC10568031 DOI: 10.3389/fnins.2023.1260675] [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: 07/18/2023] [Accepted: 09/12/2023] [Indexed: 10/17/2023] Open
Abstract
Background Subdural electrocorticography (ECoG) signals have been proposed as a stable, good-quality source for brain-machine interfaces (BMIs), with a higher spatial and temporal resolution than electroencephalography (EEG). However, long-term implantation may lead to chronic inflammatory reactions and connective tissue encapsulation, resulting in a decline in signal recording quality. However, no study has reported the effects of the surrounding tissue on signal recording and device functionality thus far. Methods In this study, we implanted a wireless recording device with a customized 32-electrode-ECoG array subdurally in two nonhuman primates for 15 months. We evaluated the neural activities recorded from and wirelessly transmitted to the devices and the chronic tissue reactions around the electrodes. In addition, we measured the gain factor of the newly formed ventral fibrous tissue in vivo. Results Time-frequency analyses of the acute and chronic phases showed similar signal features. The average root mean square voltage and power spectral density showed relatively stable signal quality after chronic implantation. Histological examination revealed thickening of the reactive tissue around the electrode array; however, no evident inflammation in the cortex. From gain factor analysis, we found that tissue proliferation under electrodes reduced the amplitude power of signals. Conclusion This study suggests that subdural ECoG may provide chronic signal recordings for future clinical applications and neuroscience research. This study also highlights the need to reduce proliferation of reactive tissue ventral to the electrodes to enhance long-term stability.
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Affiliation(s)
- Tianfang Yan
- Department of Neurological Diagnosis and Restoration, Osaka University Graduate School of Medicine, Suita, Japan
| | | | - Seiji Kameda
- Department of Neurological Diagnosis and Restoration, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masashi Maeda
- Candidate Discovery Science Labs, Astellas Pharma Inc., Tokyo, Japan
| | - Takuma Mihara
- Candidate Discovery Science Labs, Astellas Pharma Inc., Tokyo, Japan
| | - Masayuki Hirata
- Department of Neurological Diagnosis and Restoration, Osaka University Graduate School of Medicine, Suita, Japan
- Department of Neurosurgery, Osaka University Graduate School of Medicine, Suita, Japan
- Global Center for Medical Engineering and Informatics, Osaka University, Suita, Japan
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Wellman SM, Coyne OA, Douglas MM, Kozai TDY. Aberrant accumulation of age- and disease-associated factors following neural probe implantation in a mouse model of Alzheimer's disease. J Neural Eng 2023; 20:046044. [PMID: 37531953 PMCID: PMC10594264 DOI: 10.1088/1741-2552/aceca5] [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: 02/16/2023] [Revised: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 08/04/2023]
Abstract
Objective. Electrical stimulation has had a profound impact on our current understanding of nervous system physiology and provided viable clinical options for addressing neurological dysfunction within the brain. Unfortunately, the brain's immune suppression of indwelling microelectrodes currently presents a major roadblock in the long-term application of neural recording and stimulating devices. In some ways, brain trauma induced by penetrating microelectrodes produces similar neuropathology as debilitating brain diseases, such as Alzheimer's disease (AD), while also suffering from end-stage neuron loss and tissue degeneration. The goal of the present study was to understand whether there may be any parallel mechanisms at play between brain injury from chronic microelectrode implantation and those of neurodegenerative disorder.Approach. We used two-photon microscopy to visualize the accumulation, if any, of age- and disease-associated factors around chronically implanted electrodes in both young and aged mouse models of AD.Main results. We determined that electrode injury leads to aberrant accumulation of lipofuscin, an age-related pigment, in wild-type and AD mice alike. Furthermore, we reveal that chronic microelectrode implantation reduces the growth of pre-existing Alzheimer's plaques while simultaneously elevating amyloid burden at the electrode-tissue interface. Lastly, we uncover novel spatial and temporal patterns of glial reactivity, axonal and myelin pathology, and neurodegeneration related to neurodegenerative disease around chronically implanted microelectrodes.Significance. This study offers multiple novel perspectives on the possible neurodegenerative mechanisms afflicting chronic brain implants, spurring new potential avenues of neuroscience investigation and design of more targeted therapies for improving neural device biocompatibility and treatment of degenerative brain disease.
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Affiliation(s)
- Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Olivia A Coyne
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Madeline M Douglas
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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29
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Boghozian R, Sharma S, Narayana K, Cheema M, Brown CE. Sex and interferon gamma signaling regulate microglia migration in the adult mouse cortex in vivo. Proc Natl Acad Sci U S A 2023; 120:e2302892120. [PMID: 37428916 PMCID: PMC10629543 DOI: 10.1073/pnas.2302892120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 06/02/2023] [Indexed: 07/12/2023] Open
Abstract
Although microglia possess the unique ability to migrate, whether mobility is evident in all microglia, is sex dependent, and what molecular mechanisms drive this, is not well understood in the adult brain. Using longitudinal in vivo two-photon imaging of sparsely labeled microglia, we find a relatively small population of microglia (~5%) are mobile under normal conditions. Following injury (microbleed), the fraction of mobile microglia increased in a sex-dependent manner, with male microglia migrating significantly greater distances toward the microbleed relative to their female counterparts. To understand the signaling pathways involved, we interrogated the role of interferon gamma (IFNγ). Our data show that in male mice, stimulating microglia with IFNγ promotes migration whereas inhibiting IFNγ receptor 1 signaling inhibits them. By contrast, female microglia were generally unaffected by these manipulations. These findings highlight the diversity of microglia migratory responses to injury, its dependence on sex and the signaling mechanisms that modulate this behavior.
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Affiliation(s)
- Roobina Boghozian
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Sorabh Sharma
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Kamal Narayana
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Manjinder Cheema
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
| | - Craig E. Brown
- Division of Medical Sciences, University of Victoria, Victoria, BCV8P 5C2, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, BCV6T 2A1, Canada
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30
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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.
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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.
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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: 19] [Impact Index Per Article: 19.0] [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.
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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
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Wellman SM, Coyne OA, Douglas MM, Kozai TDY. Aberrant accumulation of age- and disease-associated factors following neural probe implantation in a mouse model of Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.11.528131. [PMID: 36891286 PMCID: PMC9993955 DOI: 10.1101/2023.02.11.528131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Electrical stimulation has had a profound impact on our current understanding of nervous system physiology and provided viable clinical options for addressing neurological dysfunction within the brain. Unfortunately, the brain's immune suppression of indwelling microelectrodes currently presents a major roadblock in the long-term application of neural recording and stimulating devices. In some ways, brain trauma induced by penetrating microelectrodes produces similar neuropathology as debilitating brain diseases, such as Alzheimer's disease (AD), while also suffering from end-stage neuron loss and tissue degeneration. To understand whether there may be any parallel mechanisms at play between brain injury from chronic microelectrode implantation and those of neurodegenerative disorder, we used two-photon microscopy to visualize the accumulation, if any, of age- and disease-associated factors around chronically implanted electrodes in both young and aged mouse models of AD. With this approach, we determined that electrode injury leads to aberrant accumulation of lipofuscin, an age-related pigment, in wild-type and AD mice alike. Furthermore, we reveal that chronic microelectrode implantation reduces the growth of pre-existing amyloid plaques while simultaneously elevating amyloid burden at the electrode-tissue interface. Lastly, we uncover novel spatial and temporal patterns of glial reactivity, axonal and myelin pathology, and neurodegeneration related to neurodegenerative disease around chronically implanted microelectrodes. This study offers multiple novel perspectives on the possible neurodegenerative mechanisms afflicting chronic brain implants, spurring new potential avenues of neuroscience investigation and design of more targeted therapies for improving neural device biocompatibility and treatment of degenerative brain disease.
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Zhao C, Man T, Cao Y, Weiss PS, Monbouquette HG, Andrews AM. Flexible and Implantable Polyimide Aptamer-Field-Effect Transistor Biosensors. ACS Sens 2022; 7:3644-3653. [PMID: 36399772 PMCID: PMC9982941 DOI: 10.1021/acssensors.2c01909] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Monitoring neurochemical signaling across time scales is critical to understanding how brains encode and store information. Flexible (vs stiff) devices have been shown to improve in vivo monitoring, particularly over longer times, by reducing tissue damage and immunological responses. Here, we report our initial steps toward developing flexible and implantable neuroprobes with aptamer-field-effect transistor (FET) biosensors for neurotransmitter monitoring. A high-throughput process was developed to fabricate thin, flexible polyimide probes using microelectromechanical-system (MEMS) technologies, where 150 flexible probes were fabricated on each 4 in. Si wafer. Probes were 150 μm wide and 7 μm thick with two FETs per tip. The bending stiffness was 1.2 × 10-11 N·m2. Semiconductor thin films (3 nm In2O3) were functionalized with DNA aptamers for target recognition, which produces aptamer conformational rearrangements detected via changes in FET conductance. Flexible aptamer-FET neuroprobes detected serotonin at femtomolar concentrations in high-ionic strength artificial cerebrospinal fluid. A straightforward implantation process was developed, where microfabricated Si carrier devices assisted with implantation such that flexible neuroprobes detected physiological relevant serotonin in a tissue-hydrogel brain mimic.
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Affiliation(s)
- Chuanzhen Zhao
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Tianxing Man
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Yan Cao
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States,Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Paul S. Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States,Departments of Bioengineering and Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Harold G. Monbouquette
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States,Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Anne M. Andrews
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States,Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience & Human Behavior, and Hatos Center for Neuropharmacology, University of California, Los Angeles, Los Angeles, California 90095, United States,To whom correspondence should be addressed to:
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Alahi MEE, Liu Y, Khademi S, Nag A, Wang H, Wu T, Mukhopadhyay SC. Slippery Epidural ECoG Electrode for High-Performance Neural Recording and Interface. BIOSENSORS 2022; 12:1044. [PMID: 36421162 PMCID: PMC9688081 DOI: 10.3390/bios12111044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/02/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
Chronic implantation of an epidural Electrocorticography (ECoG) electrode produces thickening of the dura mater and proliferation of the fibrosis around the interface sites, which is a significant concern for chronic neural ECoG recording applications used to monitor various neurodegenerative diseases. This study describes a new approach to developing a slippery liquid-infused porous surface (SLIPS) on the flexible ECoG electrode for a chronic neural interface with the advantage of increased cell adhesion. In the demonstration, the electrode was fabricated on the polyimide (PI) substrate, and platinum (Pt)-gray was used for creating the porous nanocone structure for infusing the silicone oil. The combination of nanocone and the infused slippery oil layer created the SLIPS coating, which has a low impedance (4.68 kΩ) level favourable for neural recording applications. The electrochemical impedance spectroscopy and equivalent circuit modelling also showed the effect of the coating on the recording site. The cytotoxicity study demonstrated that the coating does not have any cytotoxic potentiality; hence, it is biocompatible for human implantation. The in vivo (acute recording) neural recording on the rat model also confirmed that the noise level could be reduced significantly (nearly 50%) and is helpful for chronic ECoG recording for more extended neural signal recording applications.
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Affiliation(s)
- Md Eshrat E. Alahi
- The Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Yonghong Liu
- The Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Sara Khademi
- The Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- Institute of Polymeric Materials and Faculty of Polymer Engineering, Sahand University of Technology, Tabriz P.O. Box 51335/1996, Iran
| | - Anindya Nag
- Faculty of Electrical and Computer Engineering, Technische Universität Dresden, 01062 Dresden, Germany
- Centre for Tactile Internet with Human-in-the-Loop (CeTI), Technische Universität Dresden, 01069 Dresden, Germany
| | - Hao Wang
- The Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Tianzhun Wu
- The Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
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35
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Savya SP, Li F, Lam S, Wellman SM, Stieger KC, Chen K, Eles JR, Kozai TDY. In vivo spatiotemporal dynamics of astrocyte reactivity following neural electrode implantation. Biomaterials 2022; 289:121784. [PMID: 36103781 PMCID: PMC10231871 DOI: 10.1016/j.biomaterials.2022.121784] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/24/2022] [Accepted: 08/29/2022] [Indexed: 11/02/2022]
Abstract
Brain computer interfaces (BCIs), including penetrating microelectrode arrays, enable both recording and stimulation of neural cells. However, device implantation inevitably causes injury to brain tissue and induces a foreign body response, leading to reduced recording performance and stimulation efficacy. Astrocytes in the healthy brain play multiple roles including regulating energy metabolism, homeostatic balance, transmission of neural signals, and neurovascular coupling. Following an insult to the brain, they are activated and gather around the site of injury. These reactive astrocytes have been regarded as one of the main contributors to the formation of a glial scar which affects the performance of microelectrode arrays. This study investigates the dynamics of astrocytes within the first 2 weeks after implantation of an intracortical microelectrode into the mouse brain using two-photon microscopy. From our observation astrocytes are highly dynamic during this period, exhibiting patterns of process extension, soma migration, morphological activation, and device encapsulation that are spatiotemporally distinct from other glial cells, such as microglia or oligodendrocyte precursor cells. This detailed characterization of astrocyte reactivity will help to better understand the tissue response to intracortical devices and lead to the development of more effective intervention strategies to improve the functional performance of neural interfacing technology.
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Affiliation(s)
- Sajishnu P Savya
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Northwestern University, USA
| | - Fan Li
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA; Computational Modeling & Simulation PhD Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephanie Lam
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kevin C Stieger
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Keying Chen
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA.
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36
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Dobariya A, El Ahmadieh TY, Good LB, Hernandez-Reynoso AG, Jakkamsetti V, Brown R, Dunbar M, Ding K, Luna J, Kallem RR, Putnam WC, Shelton JM, Evers BM, Azami A, Geramifard N, Cogan SF, Mickey B, Pascual JM. Recording of pig neuronal activity in the comparative context of the awake human brain. Sci Rep 2022; 12:15503. [PMID: 36109613 PMCID: PMC9478131 DOI: 10.1038/s41598-022-19688-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/01/2022] [Indexed: 11/09/2022] Open
Abstract
Gyriform mammals display neurophysiological and neural network activity that other species exhibit only in rudimentary or dissimilar form. However, neural recordings from large mammals such as the pig can be anatomically hindered and pharmacologically suppressed by anesthetics. This curtails comparative inferences. To mitigate these limitations, we set out to modify electrocorticography, intracerebral depth and intracortical recording methods to study the anesthetized pig. In the process, we found that common forms of infused anesthesia such as pentobarbital or midazolam can be neurophysiologic suppressants acting in dose-independent fashion relative to anesthetic dose or brain concentration. Further, we corroborated that standard laboratory conditions may impose electrical interference with specific neural signals. We thus aimed to safeguard neural network integrity and recording fidelity by developing surgical, anesthesia and noise reduction methods and by working inside a newly designed Faraday cage, and evaluated this from the point of view of neurophysiological power spectral density and coherence analyses. We also utilized novel silicon carbide electrodes to minimize mechanical disruption of single-neuron activity. These methods allowed for the preservation of native neurophysiological activity for several hours. Pig electrocorticography recordings were essentially indistinguishable from awake human recordings except for the small segment of electrical activity associated with vision in conscious persons. In addition, single-neuron and paired-pulse stimulation recordings were feasible simultaneously with electrocorticography and depth electrode recordings. The spontaneous and stimulus-elicited neuronal activities thus surveyed can be recorded with a degree of precision similar to that achievable in rodent or any other animal studies and prove as informative as unperturbed human electrocorticography.
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Affiliation(s)
- Aksharkumar Dobariya
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd. Mail Code 8813, Dallas, TX, 75390-8813, USA
| | - Tarek Y El Ahmadieh
- Department of Neurosurgery, Loma Linda University Medical Center, Loma Linda, CA, 92354, USA
| | - Levi B Good
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd. Mail Code 8813, Dallas, TX, 75390-8813, USA
| | | | - Vikram Jakkamsetti
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd. Mail Code 8813, Dallas, TX, 75390-8813, USA
| | - Ronnie Brown
- Department of Neurological Surgery, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Misha Dunbar
- Animal Resource Center, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Kan Ding
- Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jesus Luna
- Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Raja Reddy Kallem
- Department of Pharmacy Practice and Clinical Pharmacology, Experimental Therapeutics Center, Texas Tech University Health Sciences Center, Dallas, TX, 75235, USA
| | - William C Putnam
- Department of Pharmacy Practice and Clinical Pharmacology, Experimental Therapeutics Center, Texas Tech University Health Sciences Center, Dallas, TX, 75235, USA
- Department of Pharmaceutical Science, School of Pharmacy, Texas Tech University Health Sciences Center, Dallas, TX, 75235, USA
| | - John M Shelton
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Bret M Evers
- Department of Pathology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Amirhossein Azami
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Negar Geramifard
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Stuart F Cogan
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Bruce Mickey
- Department of Neurological Surgery, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Juan M Pascual
- Rare Brain Disorders Program, Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd. Mail Code 8813, Dallas, TX, 75390-8813, USA.
- Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
- Department of Pediatrics, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
- Eugene McDermott Center for Human Growth and Development/Center for Human Genetics, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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37
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Williams NP, Kushwah N, Dhawan V, Zheng XS, Cui XT. Effects of central nervous system electrical stimulation on non-neuronal cells. Front Neurosci 2022; 16:967491. [PMID: 36188481 PMCID: PMC9521315 DOI: 10.3389/fnins.2022.967491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 08/10/2022] [Indexed: 11/13/2022] Open
Abstract
Over the past few decades, much progress has been made in the clinical use of electrical stimulation of the central nervous system (CNS) to treat an ever-growing number of conditions from Parkinson's disease (PD) to epilepsy as well as for sensory restoration and many other applications. However, little is known about the effects of microstimulation at the cellular level. Most of the existing research focuses on the effects of electrical stimulation on neurons. Other cells of the CNS such as microglia, astrocytes, oligodendrocytes, and vascular endothelial cells have been understudied in terms of their response to stimulation. The varied and critical functions of these cell types are now beginning to be better understood, and their vital roles in brain function in both health and disease are becoming better appreciated. To shed light on the importance of the way electrical stimulation as distinct from device implantation impacts non-neuronal cell types, this review will first summarize common stimulation modalities from the perspective of device design and stimulation parameters and how these different parameters have an impact on the physiological response. Following this, what is known about the responses of different cell types to different stimulation modalities will be summarized, drawing on findings from both clinical studies as well as clinically relevant animal models and in vitro systems.
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Affiliation(s)
- Nathaniel P. Williams
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States
| | - Neetu Kushwah
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Vaishnavi Dhawan
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States
| | - Xin Sally Zheng
- Department of Bioengineering, 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
- McGowan Institute for Regenerative Medicine, Pittsburgh, PA, United States
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Kushwah N, Woeppel K, Dhawan V, Shi D, Cui XT. Effects of neuronal cell adhesion molecule L1 and nanoparticle surface modification on microglia. Acta Biomater 2022; 149:273-286. [PMID: 35764240 PMCID: PMC10018678 DOI: 10.1016/j.actbio.2022.06.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 11/19/2022]
Abstract
Microelectrode arrays for neural recording suffer from low yield and stability partly due to the inflammatory host responses. A neuronal cell adhesion molecule L1 coating has been shown to promote electrode-neuron integration, reduce microglia activation and improve recording. Coupling L1 to surface via a nanoparticle (NP) base layer further increased the protein surface density and stability. However, the exact L1-microglia interaction in these coatings has not been studied. Here we cultured primary microglia on L1 modified surfaces (with and without NP) and characterized microglia activation upon phorbol myristate acetate (PMA) and lipopolysaccharide (LPS) stimulation. Results showed L1 coatings reduced microglia's superoxide production in response to PMA and presented intrinsic antioxidant properties. Meanwhile, L1 decreased iNOS, NO, and pro-inflammatory cytokines (TNF alpha, IL-6, IL-1 beta), while increased anti-inflammatory cytokines (TGF beta 1, IL-10) in LPS stimulated microglia. Furthermore, L1 increased Arg-1 expression and phagocytosis upon LPS stimulation. Rougher NP surface showed lower number of microglia attached per area than their smooth counterpart, lower IL-6 release and superoxide production, and higher intrinsic reducing potential. Finally, we examined the effect of L1 and nanoparticle modifications on microglia response in vivo over 8 weeks with 2-photon imaging. Microglial coverage on the implant surface was found to be lower on the L1 modified substrates relative to unmodified, consistent with the in vitro observation. Our results indicate L1 significantly reduces superoxide production and inflammatory response of microglia and promotes wound healing, while L1 immobilization via a nanoparticle base layer brings added benefit without adverse effects. STATEMENT OF SIGNIFICANCE: Surface modification of microelectrode arrays with L1 has been shown to reduce microglia coverage on neural probe surface in vivo and improves neural recording, but the specific mechanism of action is not fully understood. The results in this study show that surface bound L1 reduces superoxide production from cultured microglia via direct reduction reaction and signaling pathways, increases anti-inflammatory cytokine release and phagocytosis in response to PMA or LPS stimulation. Additionally, roughening the surface with nanoparticles prior to L1 immobilization further increased the benefit of L1 in reducing microglia activation and oxidative stress. Together, our findings shed light on the mechanisms of action of nanotextured and neuroadhesive neural implant coatings and guide future development of seamless tissue interface.
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Affiliation(s)
- Neetu Kushwah
- Neural Tissue/Electrode Interface and Neural Tissue Engineering lab, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Kevin Woeppel
- Neural Tissue/Electrode Interface and Neural Tissue Engineering lab, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, United States; Center for Neural Basis of Cognition, Pittsburgh, PA 15213, United States
| | - Vaishnavi Dhawan
- Neural Tissue/Electrode Interface and Neural Tissue Engineering lab, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, United States; Center for Neural Basis of Cognition, Pittsburgh, PA 15213, United States
| | - Delin Shi
- Neural Tissue/Electrode Interface and Neural Tissue Engineering lab, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, United States; Center for Neural Basis of Cognition, Pittsburgh, PA 15213, United States
| | - Xinyan Tracy Cui
- Neural Tissue/Electrode Interface and Neural Tissue Engineering lab, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, United States; McGowan Institute for Regenerative Medicine, Pittsburgh, PA 15219, United States; Center for Neural Basis of Cognition, Pittsburgh, PA 15213, United States.
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39
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Krahe DD, Woeppel KM, Yang Q, Kushwah N, Cui XT. Melatonin Decreases Acute Inflammatory Response to Neural Probe Insertion. Antioxidants (Basel) 2022; 11:antiox11081628. [PMID: 36009346 PMCID: PMC9405074 DOI: 10.3390/antiox11081628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/13/2022] [Accepted: 08/15/2022] [Indexed: 11/24/2022] Open
Abstract
Neural electrode insertion trauma impedes the recording and stimulation capabilities of numerous diagnostic and treatment avenues. Implantation leads to the activation of inflammatory markers and cell types, which is detrimental to neural tissue health and recording capabilities. Oxidative stress and inflammation at the implant site have been shown to decrease with chronic administration of antioxidant melatonin at week 16, but its effects on the acute landscape have not been studied. To assess the effect of melatonin administration in the acute phase, specifically the first week post-implantation, we utilized histological and q-PCR methods to quantify cellular and molecular indicators of inflammation and oxidative stress in the tissue surrounding implanted probes in C57BL/6 mice as well as two-photon microscopy to track the microglial responses to the probes in real-time in transgenic mice expressing GFP with CX3CR1 promotor. Histological results indicate that melatonin effectively maintained neuron density surrounding the electrode, inhibited accumulation and activation of microglia and astrocytes, and reduced oxidative tissue damage. The expression of the pro-inflammatory cytokines, TNF-α and IL-6, were significantly reduced in melatonin-treated animals. Additionally, microglial encapsulation of the implant surface was inhibited by melatonin as compared to control animals following implantation. Our results combined with previous research suggest that melatonin is a particularly suitable drug for modulating inflammatory activity around neural electrode implants both acutely and chronically, translating to more stable and reliable interfaces.
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Affiliation(s)
- Daniela D. Krahe
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Kevin M. Woeppel
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA 15213, USA
| | - Qianru Yang
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA 15213, USA
- McGowan Institute for Regenerative Medicine, Pittsburgh, PA 15219, USA
| | - Neetu Kushwah
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA 15213, USA
- McGowan Institute for Regenerative Medicine, Pittsburgh, PA 15219, USA
- Correspondence:
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Parylene C as an Insulating Polymer for Implantable Neural Interfaces: Acute Electrochemical Impedance Behaviors in Saline and Pig Brain In Vitro. Polymers (Basel) 2022; 14:polym14153033. [PMID: 35893997 PMCID: PMC9332801 DOI: 10.3390/polym14153033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/09/2022] [Accepted: 07/18/2022] [Indexed: 11/17/2022] Open
Abstract
Parylene is used as encapsulating material for medical devices due to its excellent biocompatibility and insulativity. Its performance as the insulating polymer of implantable neural interfaces has been studied in electrolyte solutions and in vivo. Biological tissue in vitro, as a potential environment for characterization and application, is convenient to access in the fabrication lab of polymer and neural electrodes, but there has been little study investigating the behaviors of Parylene in the tissue in vitro. Here, we investigated the electrochemical impedance behaviors of Parylene C polymer coating both in normal saline and in a chilled pig brain in vitro by performing electrochemical impedance spectroscopy (EIS) measurements of platinum (Pt) wire neural electrodes. The electrochemical impedance at the representative frequencies is discussed, which helps to construct the equivalent circuit model. Statistical analysis of fitted parameters of the equivalent circuit model showed good reliability of Parylene C as an insulating polymer in both electrolyte models. The electrochemical impedance measured in pig brain in vitro shows marked differences from that of saline.
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Zheng XS, Yang Q, Vazquez A, Cui XT. Imaging the stability of chronic electrical microstimulation using electrodes coated with PEDOT/CNT and iridium oxide. iScience 2022; 25:104539. [PMID: 35769881 PMCID: PMC9234710 DOI: 10.1016/j.isci.2022.104539] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 03/22/2022] [Accepted: 06/01/2022] [Indexed: 11/23/2022] Open
Abstract
Chronic microstimulation is faced with challenges that require an additional understanding of stability and safety. We implanted silicon arrays coated with poly(3,4-ethylenedioxythiophene) (PEDOT)/Carbon Nanotubes (CNT), or PCand IrOx into the cortex of GCaMP6s mice and electrically stimulated them for up to 12 weeks. We quantified neuronal responses to stimulation using two-photon imaging and mesoscale fluorescence microscopy and characterized electrode performance over time. We observed dynamic changes in stimulation stability over time and a significant advantage in energy efficiency using PC coated electrodes over IrOx coated electrodes. In a subset of mice, we observed abnormal ictal cortical responses or cortical spreading depression using stimulation parameters commonly used in intracortical stimulation applications, suggesting the need to investigate the potential neuronal damage and redefine the stimulation safety limit. This study not only revealed the dynamic changes in stimulation efficiency after implantation but also reiterates the potential for PC as a high-efficiency material in chronic neuromodulation.
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Affiliation(s)
- Xin Sally Zheng
- Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Qianru Yang
- Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
- Center for Neural Basis of Cognition, 115 Mellon Institute, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | - Alberto Vazquez
- Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
- Center for Neural Basis of Cognition, 115 Mellon Institute, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
- Department of Radiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA 15213, USA
- McGowan Institute for Regenerative Medicine, 3025 East Carson Street, Pittsburgh, PA 15219, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, 5057 Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
- Center for Neural Basis of Cognition, 115 Mellon Institute, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
- McGowan Institute for Regenerative Medicine, 3025 East Carson Street, Pittsburgh, PA 15219, USA
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Abstract
Neuroprosthetic devices that record and modulate neural activities have demonstrated immense potential for bypassing or restoring lost neurological functions due to neural injuries and disorders. However, implantable electrical devices interfacing with brain tissue are susceptible to a series of inflammatory tissue responses along with mechanical or electrical failures which can affect the device performance over time. Several biomaterial strategies have been implemented to improve device-tissue integration for high quality and stable performance. Ranging from developing smaller, softer, and more flexible electrode designs to introducing bioactive coatings and drug-eluting layers on the electrode surface, such strategies have shown different degrees of success but with limitations. With their hydrophilic properties and specific bioactivities, carbohydrates offer a potential solution for addressing some of the limitations of the existing biomolecular approaches. In this review, we summarize the role of polysaccharides in the central nervous system, with a primary focus on glycoproteins and proteoglycans, to shed light on their untapped potential as biomaterials for neural implants. Utilization of glycosaminoglycans for neural interface and tissue regeneration applications is comprehensively reviewed to provide the current state of carbohydrate-based biomaterials for neural implants. Finally, we will discuss the challenges and opportunities of applying carbohydrate-based biomaterials for neural tissue interfaces.
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Affiliation(s)
- Vaishnavi Dhawan
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for Neural Basis of Cognition, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA
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43
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Urdaneta ME, Kunigk NG, Currlin S, Delgado F, Fried SI, Otto KJ. The Long-Term Stability of Intracortical Microstimulation and the Foreign Body Response Are Layer Dependent. Front Neurosci 2022; 16:908858. [PMID: 35769707 PMCID: PMC9234554 DOI: 10.3389/fnins.2022.908858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/16/2022] [Indexed: 11/24/2022] Open
Abstract
Intracortical microstimulation (ICMS) of the somatosensory cortex (S1) can restore sensory function in patients with paralysis. Studies assessing the stability of ICMS have reported heterogeneous responses across electrodes and over time, potentially hindering the implementation and translatability of these technologies. The foreign body response (FBR) and the encapsulating glial scar have been associated with a decay in chronic performance of implanted electrodes. Moreover, the morphology, intrinsic properties, and function of cells vary across cortical layers, each potentially affecting the sensitivity to ICMS as well as the degree of the FBR across cortical depth. However, layer-by-layer comparisons of the long-term stability of ICMS as well as the extent of the astrocytic glial scar change across cortical layers have not been well explored. Here, we implanted silicon microelectrodes with electrode sites spanning all the layers of S1 in rats. Using a behavioral paradigm, we obtained ICMS detection thresholds from all cortical layers for up to 40 weeks. Our results showed that the sensitivity and long-term performance of ICMS is indeed layer dependent. Overall, detection thresholds decreased during the first 7 weeks post-implantation (WPI). This was followed by a period in which thresholds remained stable or increased depending on the interfacing layer: thresholds in L1 and L6 exhibited the most consistent increases over time, while those in L4 and L5 remained the most stable. Furthermore, histological investigation of the tissue surrounding the electrode showed a biological response of microglia and macrophages which peaked at L1, while the area of the astrocytic glial scar peaked at L2/3. Interestingly, the biological response of these FBR markers is less exacerbated at L4 and L5, suggesting a potential link between the FBR and the long-term stability of ICMS. These findings suggest that interfacing depth can play an important role in the design of chronically stable implantable microelectrodes.
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Affiliation(s)
- Morgan E. Urdaneta
- Department of Neuroscience, University of Florida, Gainesville, FL, United States
- *Correspondence: Morgan E. Urdaneta,
| | - Nicolas G. Kunigk
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Seth Currlin
- Department of Neuroscience, University of Florida, Gainesville, FL, United States
| | - Francisco Delgado
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
| | - Shelley I. Fried
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
- Boston Veterans Affairs Healthcare System, Boston, MA, United States
| | - Kevin J. Otto
- Department of Neuroscience, University of Florida, Gainesville, FL, United States
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, United States
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL, United States
- Department of Neurology, University of Florida, Gainesville, FL, United States
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL, United States
- Kevin J. Otto,
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44
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Stieger KC, Eles JR, Ludwig K, Kozai TDY. Intracortical microstimulation pulse waveform and frequency recruits distinct spatiotemporal patterns of cortical neuron and neuropil activation. J Neural Eng 2022; 19. [PMID: 35263736 DOI: 10.1088/1741-2552/ac5bf5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/09/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Neural prosthetics often use intracortical microstimulation (ICMS) for sensory restoration. To restore natural and functional feedback, we must first understand how stimulation parameters influence the recruitment of neural populations. ICMS waveform asymmetry modulates the spatial activation of neurons around an electrode at 10 Hz; however, it is unclear how asymmetry may differentially modulate population activity at frequencies typically employed in the clinic (e.g. 100 Hz). We hypothesized that stimulation waveform asymmetry would differentially modulate preferential activation of certain neural populations, and the differential population activity would be frequency-dependent. APPROACH We quantified how asymmetric stimulation waveforms delivered at 10 Hz or 100 Hz for 30s modulated spatiotemporal activity of cortical layer II/III pyramidal neurons using in vivo two-photon and mesoscale calcium imaging in anesthetized mice. Asymmetry is defined in terms of the ratio of the duration of the leading phase to the duration of the return phase of charge-balanced cathodal- and anodal-first waveforms (i.e. longer leading phase relative to return has larger asymmetry). MAIN RESULTS Neurons within 40-60µm of the electrode display stable stimulation-induced activity indicative of direct activation, which was independent of waveform asymmetry. The stability of 72% of activated neurons and the preferential activation of 20-90 % of neurons depended on waveform asymmetry. Additionally, this asymmetry-dependent activation of different neural populations was associated with differential progression of population activity. Specifically, neural activity tended to increase over time during 10 hz stimulation for some waveforms, whereas activity remained at the same level throughout stimulation for other waveforms. During 100 Hz stimulation, neural activity decreased over time for all waveforms, but decreased more for the waveforms that resulted in increasing neural activity during 10 Hz stimulation. SIGNIFICANCE These data demonstrate that at frequencies commonly used for sensory restoration, stimulation waveform alters the pattern of activation of different but overlapping populations of excitatory neurons. The impact of these waveform specific responses on the activation of different subtypes of neurons as well as sensory perception merits further investigation.
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Affiliation(s)
- Kevin C Stieger
- Bioengineering, University of Pittsburgh, 300 Technology Dr, Pittsburgh, Pennsylvania, 15219, UNITED STATES
| | - James Regis Eles
- Department of Bioengineering, University of Pittsburgh, 300 Technology Dr, Pittsburgh, Pennsylvania, 15219, UNITED STATES
| | - Kip Ludwig
- Biomedical Engineering and Neurological Surgery, University of Wisconsin Madison, XXX, Madison, Wisconsin, 53706, UNITED STATES
| | - Takashi D Yoshida Kozai
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave, 5059-BST3, Pittsburgh, PA 15213, USA, Pittsburgh, Pennsylvania, 15219, UNITED STATES
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45
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Yamashita K, Sawahata H, Yamagiwa S, Yokoyama S, Numano R, Koida K, Kawano T. A floating 5 μm-diameter needle electrode on the tissue for damage-reduced chronic neuronal recording in mice. LAB ON A CHIP 2022; 22:747-756. [PMID: 35044407 DOI: 10.1039/d1lc01031j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Microelectrode technology is essential in electrophysiology and has made contributions to neuroscience as well as to medical applications. However, it is necessary to minimize tissue damage associated with needle-like electrode on the brain tissue and the implantation surgery, which makes stable chronic recording impossible. Here, we report on an approach for using a 5 μm-diameter needle electrode, which enables the following of tissue motions, via a surgical method. The electrode is placed on the brain tissue of a mouse with a dissolvable material, reducing the physical stress to the tissue; this is followed by the implantation of the electrode device in the brain without fixing it to the cranium, achieving a floating electrode architecture on the tissue. The electrode shows stable recording with no significant degradation of the signal-to-noise ratios for 6 months, and minimized tissue damage is confirmed compared to that when using a cranium-fixed electrode with the same needle geometry.
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Affiliation(s)
- Koji Yamashita
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Aichi, Japan.
| | | | - Shota Yamagiwa
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Aichi, Japan.
| | | | - Rika Numano
- Electronics-Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, Aichi, Japan
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, Aichi, Japan
| | - Kowa Koida
- Electronics-Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, Aichi, Japan
- Department of Computer Science and Engineering, Toyohashi University of Technology, Aichi, Japan
| | - Takeshi Kawano
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Aichi, Japan.
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46
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Otte E, Vlachos A, Asplund M. Engineering strategies towards overcoming bleeding and glial scar formation around neural probes. Cell Tissue Res 2022; 387:461-477. [PMID: 35029757 PMCID: PMC8975777 DOI: 10.1007/s00441-021-03567-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/17/2021] [Indexed: 12/15/2022]
Abstract
Neural probes are sophisticated electrophysiological tools used for intra-cortical recording and stimulation. These microelectrode arrays, designed to penetrate and interface the brain from within, contribute at the forefront of basic and clinical neuroscience. However, one of the challenges and currently most significant limitations is their ‘seamless’ long-term integration into the surrounding brain tissue. Following implantation, which is typically accompanied by bleeding, the tissue responds with a scarring process, resulting in a gliotic region closest to the probe. This glial scarring is often associated with neuroinflammation, neurodegeneration, and a leaky blood–brain interface (BBI). The engineering progress on minimizing this reaction in the form of improved materials, microfabrication, and surgical techniques is summarized in this review. As research over the past decade has progressed towards a more detailed understanding of the nature of this biological response, it is time to pose the question: Are penetrating probes completely free from glial scarring at all possible?
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47
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The Effects of Modified Curcumin Preparations on Glial Morphology in Aging and Neuroinflammation. Neurochem Res 2022; 47:813-824. [PMID: 34988899 DOI: 10.1007/s11064-021-03499-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 11/26/2021] [Accepted: 11/27/2021] [Indexed: 12/14/2022]
Abstract
Neuroinflammation is characterized by reactive microglia and astrocytes (collectively called gliosis) in the central nervous system and is considered as one of the main pathological hallmarks in different neurodegenerative diseases such as Alzheimer's disease, age-related dementia, and multiple sclerosis. Upon activation, glia undergoes structural and morphological changes such as the microglial cells swell in size and astrocytes become bushy, which play both beneficial and detrimental roles. Hence, they are unable to perform the normal physiological role in brain immunity. Curcumin, a cytokine suppressive anti-inflammatory drug, has a high proven pre-clinical potency and efficacy to reverse chronic neuroinflammation by attenuating the activation and morphological changes that occur in the microglia and astrocytes. This review will highlight the recent findings on the tree structure changes of microglia and astrocytes in neuroinflammation and the effects of curcumin against the activation and morphology of glial cells.
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48
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Gulino M, Santos SD, Pêgo AP. Biocompatibility of Platinum Nanoparticles in Brain ex vivo Models in Physiological and Pathological Conditions. Front Neurosci 2022; 15:787518. [PMID: 34975386 PMCID: PMC8714788 DOI: 10.3389/fnins.2021.787518] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/26/2021] [Indexed: 12/22/2022] Open
Abstract
Platinum nanoparticles (PtNPs) have unique physico-chemical properties that led to their use in many branches of medicine. Recently, PtNPs gathered growing interest as delivery vectors for drugs, biosensors and as surface coating on chronically implanted biomedical devices for improving electrochemical properties. However, there are contradictory statements about their biocompatibility and impact on target organs such as the brain tissue, where these NPs are finding many applications. Furthermore, many of the reported studies are conducted in homeostasis conditions and, consequently, neglect the impact of the pathologic conditions on the tissue response. To expand our knowledge on the effects of PtNPs on neuronal and glial cells, we investigated the acute effects of monodisperse sodium citrate-coated PtNPs on rat organotypic hippocampal cultures in physiological or neuronal excitotoxic conditions induced by kainic acid (KA). The cellular responses of the PtNPs were evaluated through cytotoxic assays and confocal microscopy analysis. To mimic a pathologic scenario, 7-day organotypic hippocampal cultures were exposed to KA for 24 h. Subsequently, PtNPs were added to each slice. We show that incubation of the slices with PtNPs for 24 h, does not severely impact cell viability in normal conditions, with no significant differences when comparing the dentate gyrus (DG), as well as CA3 and CA1 pyramidal cell layers. Such effects are not exacerbated in KA-treated slices, where the presence of PtNPs does not cause additional neuronal propidium iodide (PI) uptake in CA3 and CA1 pyramidal cell layers. However, PtNPs cause microglial cell activation and morphological alterations in CA3 and DG regions indicating the establishment of an inflammatory reaction. Morphological analysis revealed that microglia acquire activated ameboid morphology with loss of ramifications, as a result of their response to PtNPs contact. Surprisingly, this effect is not increased in pathological conditions. Taken together, these results show that PtNPs cause microglia alterations in short-term studies. Additionally, there is no worsening of the tissue response in a neuropathological induced scenario. This work highlights the need of further research to allow for the safe use of PtNPs. Also, it supports the demand of the development of novel and more biocompatible NPs to be applied in the brain.
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Affiliation(s)
- Maurizio Gulino
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,FEUP - Faculdade de Engenharia da Universidade do Porto, Porto, Portugal
| | - Sofia Duque Santos
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - Ana Paula Pêgo
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,FEUP - Faculdade de Engenharia da Universidade do Porto, Porto, Portugal.,ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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49
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Jang JW, Kang YN, Seo HW, Kim B, Choe HK, Park SH, Lee MG, Kim S. Long-term in-vivorecording performance of flexible penetrating microelectrode arrays. J Neural Eng 2021; 18. [PMID: 34795067 DOI: 10.1088/1741-2552/ac3656] [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: 08/10/2021] [Accepted: 11/02/2021] [Indexed: 11/12/2022]
Abstract
Objective. Neural interfaces are an essential tool to enable the human body to directly communicate with machines such as computers or prosthetic robotic arms. Since invasive electrodes can be located closer to target neurons, they have advantages such as precision in stimulation and high signal-to-noise ratio (SNR) in recording, while they often exhibit unstable performance in long-termin-vivoimplantation because of the tissue damage caused by the electrodes insertion. In the present study, we investigated the electrical functionality of flexible penetrating microelectrode arrays (FPMAs) up to 3 months inin-vivoconditions.Approach. Thein-vivoexperiment was performed by implanting FPMAs in five rats. Thein-vivoimpedance as well as the action potential (AP) amplitude and SNR were analyzed over weeks. Additionally, APs were tracked over time to investigate the possibility of single neuron recording.Main results. It was observed that the FPMAs exhibited dramatic increases in impedance for the first 4 weeks after implantation, accompanied by decreases in AP amplitude. However, the increase/decrease in AP amplitude was always accompanied by the increase/decrease in background noise, resulting in quite consistently maintained SNRs. After 4 weeks of implantation, we observed two distinctive issues regarding long-term implantation, each caused by chronic tissue responses or by the delamination of insulation layer. The results demonstrate that the FPMAs successfully recorded neuronal signals up to 12 weeks, with very stably maintained SNRs, reduced by only 16.1% on average compared to the first recordings, although biological tissue reactions or physical degradation of the FPMA were present.Significance. The fabricated FPMAs successfully recorded intracortical signals for 3 months. The SNR was maintained up to 3 months and the chronic function of FPMA was comparable with other silicon based implantable electrodes.
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Affiliation(s)
- Jae-Won Jang
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Yoo Na Kang
- Department of Medical Assistant Robot, Korea Institute of Machinery and Materials (KIMM), Daegu, Republic of Korea
| | - Hee Won Seo
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Boil Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Han Kyoung Choe
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Sang Hyun Park
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
| | - Maan-Gee Lee
- Department of Pharmacology, School of MedicineKyungpook National University, Daegu, Republic of Korea.,Brain Science and Engineering Institute, Kyungpook National University, Daegu, Republic of Korea
| | - Sohee Kim
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
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50
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Seaton BT, Heien ML. Biocompatible reference electrodes to enhance chronic electrochemical signal fidelity in vivo. Anal Bioanal Chem 2021; 413:6689-6701. [PMID: 34595560 DOI: 10.1007/s00216-021-03640-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 12/17/2022]
Abstract
In vivo electrochemistry is a vital tool of neuroscience that allows for the detection, identification, and quantification of neurotransmitters, their metabolites, and other important analytes. One important goal of in vivo electrochemistry is a better understanding of progressive neurological disorders (e.g., Parkinson's disease). A complete understanding of such disorders can only be achieved through a combination of acute (i.e., minutes to hours) and chronic (i.e., days or longer) experimentation. Chronic studies are more challenging because they require prolonged implantation of electrodes, which elicits an immune response, leading to glial encapsulation of the electrodes and altered electrode performance (i.e., biofouling). Biofouling leads to increased electrode impedance and reference electrode polarization, both of which diminish the selectivity and sensitivity of in vivo electrochemical measurements. The increased impedance factor has been successfully mitigated previously with the use of a counter electrode, but the challenge of reference electrode polarization remains. The commonly used Ag/AgCl reference electrode lacks the long-term potential stability in vivo required for chronic measurements. In addition, the cytotoxicity of Ag/AgCl adversely affects animal experimentation and prohibits implantation in humans, hindering translational research progress. Thus, a move toward biocompatible reference electrodes with superior chronic potential stability is necessary. Two qualifying materials, iridium oxide and boron-doped diamond, are introduced and discussed in terms of their electrochemical properties, biocompatibilities, fabrication methods, and applications. In vivo electrochemistry continues to advance toward more chronic experimentation in both animal models and humans, necessitating the utilization of biocompatible reference electrodes that should provide superior potential stability and allow for unprecedented chronic signal fidelity when used with a counter electrode for impedance mitigation.
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Affiliation(s)
- Blake T Seaton
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA
| | - Michael L Heien
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA.
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