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Duan W, Robles UA, Poole‐Warren L, Esrafilzadeh D. Bioelectronic Neural Interfaces: Improving Neuromodulation Through Organic Conductive Coatings. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2306275. [PMID: 38115740 PMCID: PMC11251570 DOI: 10.1002/advs.202306275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/07/2023] [Indexed: 12/21/2023]
Abstract
Integration of bioelectronic devices in clinical practice is expanding rapidly, focusing on conditions ranging from sensory to neurological and mental health disorders. While platinum (Pt) electrodes in neuromodulation devices such as cochlear implants and deep brain stimulators have shown promising results, challenges still affect their long-term performance. Key among these are electrode and device longevity in vivo, and formation of encapsulating fibrous tissue. To overcome these challenges, organic conductors with unique chemical and physical properties are being explored. They hold great promise as coatings for neural interfaces, offering more rapid regulatory pathways and clinical implementation than standalone bioelectronics. This study provides a comprehensive review of the potential benefits of organic coatings in neuromodulation electrodes and the challenges that limit their effective integration into existing devices. It discusses issues related to metallic electrode use and introduces physical, electrical, and biological properties of organic coatings applied in neuromodulation. Furthermore, previously reported challenges related to organic coating stability, durability, manufacturing, and biocompatibility are thoroughly reviewed and proposed coating adhesion mechanisms are summarized. Understanding organic coating properties, modifications, and current challenges of organic coatings in clinical and industrial settings is expected to provide valuable insights for their future development and integration into organic bioelectronics.
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Affiliation(s)
- Wenlu Duan
- The Graduate School of Biomedical EngineeringUNSWSydneyNSW2052Australia
| | | | - Laura Poole‐Warren
- The Graduate School of Biomedical EngineeringUNSWSydneyNSW2052Australia
- Tyree Foundation Institute of Health EngineeringUNSWSydneyNSW2052Australia
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2
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Sands I, Demarco R, Thurber L, Esteban-Linares A, Song D, Meng E, Chen Y. Interface-Mediated Neurogenic Signaling: The Impact of Surface Geometry and Chemistry on Neural Cell Behavior for Regenerative and Brain-Machine Interfacing Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2401750. [PMID: 38961531 DOI: 10.1002/adma.202401750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 06/17/2024] [Indexed: 07/05/2024]
Abstract
Nanomaterial advancements have driven progress in central and peripheral nervous system applications such as tissue regeneration and brain-machine interfacing. Ideally, neural interfaces with native tissue shall seamlessly integrate, a process that is often mediated by the interfacial material properties. Surface topography and material chemistry are significant extracellular stimuli that can influence neural cell behavior to facilitate tissue integration and augment therapeutic outcomes. This review characterizes topographical modifications, including micropillars, microchannels, surface roughness, and porosity, implemented on regenerative scaffolding and brain-machine interfaces. Their impact on neural cell response is summarized through neurogenic outcome and mechanistic analysis. The effects of surface chemistry on neural cell signaling with common interfacing compounds like carbon-based nanomaterials, conductive polymers, and biologically inspired matrices are also reviewed. Finally, the impact of these extracellular mediated neural cues on intracellular signaling cascades is discussed to provide perspective on the manipulation of neuron and neuroglia cell microenvironments to drive therapeutic outcomes.
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Affiliation(s)
- Ian Sands
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, 06269, USA
| | - Ryan Demarco
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, 06269, USA
| | - Laura Thurber
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, 06269, USA
| | - Alberto Esteban-Linares
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Dong Song
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Ellis Meng
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - Yupeng Chen
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, 06269, USA
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3
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Boys AJ. There and Back Again: Building Systems That Integrate, Interface, and Interact with the Human Body. Adv Biol (Weinh) 2024; 8:e2300366. [PMID: 38400703 DOI: 10.1002/adbi.202300366] [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: 07/23/2023] [Revised: 01/31/2024] [Indexed: 02/25/2024]
Abstract
Since Dr. Theodor Schwann posed the extension of Cell Theory to mammals in 1839, scientists have dreamt up ways to interface with and influence the cells. Recently, considerable ground in this area is gained, particularly in the scope of bioelectronics. New advances in this area have provided with a means to record electrical activity from cells, examining neural firing or epithelial barrier integrity, and stimulate cells through applied electrical fields. Many of these applications utilize invasive implantation systems to perform this interaction in close proximity to the cells in question. Traditionally, the body's immune system fights back against these systems through the foreign body response, limiting the efficacy of long-term interactions. New technologies in tissue engineering, biomaterials science, and bioelectronics offer the potential to circumvent the foreign body response and create stable long-term biological interfaces. Looking ahead, the next advancements in the biomedical sciences can truly integrate, interface, and interact with the human body.
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Affiliation(s)
- Alexander J Boys
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, CB3 0AS, UK
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4
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Wu J, Xue W, Yun Z, Liu Q, Sun X. Biomedical applications of stimuli-responsive "smart" interpenetrating polymer network hydrogels. Mater Today Bio 2024; 25:100998. [PMID: 38390342 PMCID: PMC10882133 DOI: 10.1016/j.mtbio.2024.100998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/04/2024] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
In recent years, owing to the ongoing advancements in polymer materials, hydrogels have found increasing applications in the biomedical domain, notably in the realm of stimuli-responsive "smart" hydrogels. Nonetheless, conventional single-network stimuli-responsive "smart" hydrogels frequently exhibit deficiencies, including low mechanical strength, limited biocompatibility, and extended response times. In response, researchers have addressed these challenges by introducing a second network to create stimuli-responsive "smart" Interpenetrating Polymer Network (IPN) hydrogels. The mechanical strength of the material can be significantly improved due to the topological entanglement and physical interactions within the interpenetrating structure. Simultaneously, combining different network structures enhances the biocompatibility and stimulus responsiveness of the gel, endowing it with unique properties such as cell adhesion, conductivity, hemostasis/antioxidation, and color-changing capabilities. This article primarily aims to elucidate the stimulus-inducing factors in stimuli-responsive "smart" IPN hydrogels, the impact of the gels on cell behaviors and their biomedical application range. Additionally, we also offer an in-depth exposition of their categorization, mechanisms, performance characteristics, and related aspects. This review furnishes a comprehensive assessment and outlook for the advancement of stimuli-responsive "smart" IPN hydrogels within the biomedical arena. We believe that, as the biomedical field increasingly demands novel materials featuring improved mechanical properties, robust biocompatibility, and heightened stimulus responsiveness, stimuli-responsive "smart" IPN hydrogels will hold substantial promise for wide-ranging applications in this domain.
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Affiliation(s)
- Jiuping Wu
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Wu Xue
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun, 130041, China
| | - Zhihe Yun
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun, 130041, China
| | - Qinyi Liu
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun, 130041, China
| | - Xinzhi Sun
- Department of Orthopedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
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5
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Sha B, Du Z. Neural repair and regeneration interfaces: a comprehensive review. Biomed Mater 2024; 19:022002. [PMID: 38232383 DOI: 10.1088/1748-605x/ad1f78] [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: 05/31/2023] [Accepted: 01/17/2024] [Indexed: 01/19/2024]
Abstract
Neural interfaces play a pivotal role in neuromodulation, as they enable precise intervention into aberrant neural activity and facilitate recovery from neural injuries and resultant functional impairments by modulating local immune responses and neural circuits. This review outlines the development and applications of these interfaces and highlights the advantages of employing neural interfaces for neural stimulation and repair, including accurate targeting of specific neural populations, real-time monitoring and control of neural activity, reduced invasiveness, and personalized treatment strategies. Ongoing research aims to enhance the biocompatibility, stability, and functionality of these interfaces, ultimately augmenting their therapeutic potential for various neurological disorders. The review focuses on electrophysiological and optophysiology neural interfaces, discussing functionalization and power supply approaches. By summarizing the techniques, materials, and methods employed in this field, this review aims to provide a comprehensive understanding of the potential applications and future directions for neural repair and regeneration devices.
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Affiliation(s)
- Baoning Sha
- Brain Cognition and Brain Disease Institute, CAS Key Laboratory of Brain Connectome and Manipulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, Shenzhen institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China
- Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Fundamental Research Institutions, Shenzhen, People's Republic of China
- Department of Biomedical Engineering, Columbia University, New York, NY, United States of America
| | - Zhanhong Du
- Brain Cognition and Brain Disease Institute, CAS Key Laboratory of Brain Connectome and Manipulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, Shenzhen institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China
- Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Fundamental Research Institutions, Shenzhen, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, People's Republic of China
- Faculty of Life and Health Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China
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6
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Sait R, Al-Jawhari H, Ganash A, Wustoni S, Chen L, Hedhili MN, Wehbe N, Hussein D, Alhowity A, Baeesa S, Bangash M, Abuzenadah A, Inal S, Cross R. Electrochemical Performance of Biocompatible TiC Films Deposited through Nonreactive RF Magnetron Sputtering for Neural Interfacing. ACS Biomater Sci Eng 2024; 10:391-404. [PMID: 38095213 DOI: 10.1021/acsbiomaterials.3c01371] [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] [Indexed: 01/09/2024]
Abstract
The efficacy of neural electrode stimulation and recording hinges significantly on the choice of a neural electrode interface material. Transition metal carbides (TMCs), particularly titanium carbide (TiC), have demonstrated exceptional chemical stability and high electrical conductivity. Yet, the fabrication of TiC thin films and their potential application as neural electrode interfaces remains relatively unexplored. Herein, we present a systematic examination of TiC thin films synthesized through nonreactive radio frequency (RF) magnetron sputtering. TiC films were optimized toward high areal capacitance, low impedance, and stable electrochemical cyclability. We varied the RF power and deposition pressure to pinpoint the optimal properties, focusing on the deposition rate, surface roughness, crystallinity, and elemental composition to achieve high areal capacitance and low impedance. The best-performing TiC film showed an areal capacitance of 475 μF/cm2 with a capacitance retention of 93% after 5000 cycles. In addition, the electrochemical performance of the optimum film under varying scanning rates demonstrated a stable electrochemical performance even under dynamic and fast-changing stimulation conditions. Furthermore, the in vitro cell culture for 3 weeks revealed excellent biocompatibility, promoting cell growth compared with a control substrate. This work presents a novel contribution, highlighting the potential of sputtered TiC thin films as robust neural electrode interface materials.
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Affiliation(s)
- Roaa Sait
- Faculty of Science, Department of Physics, King Abdulaziz University, Building 7, P.O. Box 80203, Jeddah 21589, Saudi Arabia
| | - Hala Al-Jawhari
- Faculty of Science, Department of Physics, King Abdulaziz University, Building 7, P.O. Box 80203, Jeddah 21589, Saudi Arabia
| | - Aisha Ganash
- Faculty of Science, Department of Physics, King Abdulaziz University, Building 7, P.O. Box 80203, Jeddah 21589, Saudi Arabia
| | - Shofarul Wustoni
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Building 2, Thuwal 23955-6900, Saudi Arabia
| | - Long Chen
- Imaging and Characterization Core Laboratories, King Abdullah University of Science and Engineering (KAUST), Building 3, Thuwal 23955-6900, Saudi Arabia
| | - Mohamed Nejib Hedhili
- Imaging and Characterization Core Laboratories, King Abdullah University of Science and Engineering (KAUST), Building 3, Thuwal 23955-6900, Saudi Arabia
| | - Nimer Wehbe
- Imaging and Characterization Core Laboratories, King Abdullah University of Science and Engineering (KAUST), Building 3, Thuwal 23955-6900, Saudi Arabia
| | - Deema Hussein
- King Fahd Medical Research Center, Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, P.O. Box 80216, Jeddah 21589, Saudi Arabia
| | - Alazouf Alhowity
- King Fahd Medical Research Center, Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, P.O. Box 80216, Jeddah 21589, Saudi Arabia
| | - Saleh Baeesa
- King Fahd Medical Research Center, Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, P.O. Box 80216, Jeddah 21589, Saudi Arabia
| | - Mohammed Bangash
- King Fahd Medical Research Center, Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, P.O. Box 80216, Jeddah 21589, Saudi Arabia
| | - Adel Abuzenadah
- King Fahd Medical Research Center, Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, P.O. Box 80216, Jeddah 21589, Saudi Arabia
| | - Sahika Inal
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Building 2, Thuwal 23955-6900, Saudi Arabia
| | - Richard Cross
- Emerging Technology Research Center, De Montfort University, The Gateway, Leicester LE1 9BH, United Kingdom
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7
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Aktas B, Ozgun A, Kilickap BD, Garipcan B. Cell adhesion molecule immobilized gold surfaces for enhanced neuron-electrode interfaces. J Biomed Mater Res B Appl Biomater 2024; 112:e35310. [PMID: 37950592 DOI: 10.1002/jbm.b.35310] [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: 02/06/2023] [Revised: 06/24/2023] [Accepted: 07/31/2023] [Indexed: 11/12/2023]
Abstract
To provide a long-term solution for increasing the biocompatibility of neuroprosthetics, approaches to reduce the side effects of invasive neuro-implantable devices are still in need of improvement. Physical, chemical, and bioactive design aspects of the biomaterials are proven to be important for providing proper cell-to-cell, cell-to-material interactions. Particularly, modification of implant surfaces with bioactive cues, especially cell adhesion molecules (CAMs) that capitalize on native neural adhesion mechanisms, are promising candidates in favor of providing efficient interfaces. Within this concept, this study utilized specific CAMs, namely N-Cadherin (Neural cadherin, N-Cad) and neural cell adhesion molecule (NCAM), to enhance neuron-electrode contact by mimicking the cell-to-ECM interactions for improving the survival of cells and promoting neurite outgrowth. For this purpose, representative gold electrode surfaces were modified with N-Cadherin, NCAM, and the mixture (1:1) of these molecules. Modifications were characterized, and the effect of surface modification on both differentiated and undifferentiated neuroblastoma SH-SY5Y cell lines were compared. The findings demonstrated the successful modification of these molecules which subsequently exhibited biocompatible properties as evidenced by the cell viability results. In cell culture experiments, the CAMs displayed promising results in promoting neurite outgrowth compared to conventional poly-l-lysine coated surfaces, especially NCAM and N-Cad/NCAM modified surfaces clearly showed significant improvement. Overall, this optimized approach is expected to provide an insight into the action mechanisms of cells against the local environment and advance processes for the fabrication of alternative neural interfaces.
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Affiliation(s)
- Bengu Aktas
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Alp Ozgun
- Department of Mechanical Engineering, Faculty of Engineering, University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Bora Garipcan
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
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8
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Cho W, Yoon SH, Chung TD. Streamlining the interface between electronics and neural systems for bidirectional electrochemical communication. Chem Sci 2023; 14:4463-4479. [PMID: 37152246 PMCID: PMC10155913 DOI: 10.1039/d3sc00338h] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/13/2023] [Indexed: 05/09/2023] Open
Abstract
Seamless neural interfaces conjoining neurons and electrochemical devices hold great potential for highly efficient signal transmission across neural systems and the external world. Signal transmission through chemical sensing and stimulation via electrochemistry is remarkable because communication occurs through the same chemical language of neurons. Emerging strategies based on synaptic interfaces, iontronics-based neuromodulation, and improvements in selective neurosensing techniques have been explored to achieve seamless integration and efficient neuro-electronics communication. Synaptic interfaces can directly exchange signals to and from neurons, in a similar manner to that of chemical synapses. Hydrogel-based iontronic chemical delivery devices are operationally compatible with neural systems for improved neuromodulation. In this perspective, we explore developments to improve the interface between neurons and electrodes by targeting neurons or sub-neuronal regions including synapses. Furthermore, recent progress in electrochemical neurosensing and iontronics-based chemical delivery is examined.
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Affiliation(s)
- Wonkyung Cho
- Department of Chemistry, Seoul National University Seoul 08826 Republic of Korea
| | - Sun-Heui Yoon
- Department of Chemistry, Seoul National University Seoul 08826 Republic of Korea
| | - Taek Dong Chung
- Department of Chemistry, Seoul National University Seoul 08826 Republic of Korea
- Advanced Institutes of Convergence Technology Suwon-si 16229 Gyeonggi-do Republic of Korea
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9
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Rochford AE, Carnicer-Lombarte A, Kawan M, Jin A, Hilton S, Curto VF, Rutz AL, Moreau T, Kotter MR, Malliaras GG, Barone DG. Functional neurological restoration of amputated peripheral nerve using biohybrid regenerative bioelectronics. SCIENCE ADVANCES 2023; 9:eadd8162. [PMID: 36947608 PMCID: PMC10032597 DOI: 10.1126/sciadv.add8162] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
The development of neural interfaces with superior biocompatibility and improved tissue integration is vital for treating and restoring neurological functions in the nervous system. A critical factor is to increase the resolution for mapping neuronal inputs onto implants. For this purpose, we have developed a new category of neural interface comprising induced pluripotent stem cell (iPSC)-derived myocytes as biological targets for peripheral nerve inputs that are grafted onto a flexible electrode arrays. We show long-term survival and functional integration of a biohybrid device carrying human iPSC-derived cells with the forearm nerve bundle of freely moving rats, following 4 weeks of implantation. By improving the tissue-electronics interface with an intermediate cell layer, we have demonstrated enhanced resolution and electrical recording in vivo as a first step toward restorative therapies using regenerative bioelectronics.
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Affiliation(s)
- Amy E. Rochford
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | | | - Malak Kawan
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Amy Jin
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Sam Hilton
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Vincenzo F. Curto
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Alexandra L. Rutz
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | | | - Mark R. N. Kotter
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Bit Bio, Cambridge, UK
| | - George G. Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Damiano G. Barone
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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10
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Kaniewska K, Marcisz K, Karbarz M. Transport of ionic species affected by interactions with a pH-sensitive monolayer of microgel particles attached to electrode surface. J Electroanal Chem (Lausanne) 2023. [DOI: 10.1016/j.jelechem.2023.117183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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11
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Erofeev A, Antifeev I, Bolshakova A, Bezprozvanny I, Vlasova O. In Vivo Penetrating Microelectrodes for Brain Electrophysiology. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22239085. [PMID: 36501805 PMCID: PMC9735502 DOI: 10.3390/s22239085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/14/2022] [Accepted: 11/22/2022] [Indexed: 05/13/2023]
Abstract
In recent decades, microelectrodes have been widely used in neuroscience to understand the mechanisms behind brain functions, as well as the relationship between neural activity and behavior, perception and cognition. However, the recording of neuronal activity over a long period of time is limited for various reasons. In this review, we briefly consider the types of penetrating chronic microelectrodes, as well as the conductive and insulating materials for microelectrode manufacturing. Additionally, we consider the effects of penetrating microelectrode implantation on brain tissue. In conclusion, we review recent advances in the field of in vivo microelectrodes.
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Affiliation(s)
- Alexander Erofeev
- Laboratory of Molecular Neurodegeneration, Graduate School of Biomedical Systems and Technologies, Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
- Correspondence: (A.E.); (O.V.)
| | - Ivan Antifeev
- Laboratory of Methods and Instruments for Genetic and Immunoassay Analysis, Institute for Analytical Instrumentation of the Russian Academy of Sciences, 198095 Saint Petersburg, Russia
| | - Anastasia Bolshakova
- Laboratory of Molecular Neurodegeneration, Graduate School of Biomedical Systems and Technologies, Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Graduate School of Biomedical Systems and Technologies, Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Olga Vlasova
- Laboratory of Molecular Neurodegeneration, Graduate School of Biomedical Systems and Technologies, Institute of Biomedical Systems and Biotechnology, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
- Correspondence: (A.E.); (O.V.)
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12
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Rao L, Liu Y, Zhou H. Significantly improved cell affinity of polydimethylsiloxane enabled by a surface-modified strategy with chemical coupling. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2022; 33:66. [PMID: 36138160 PMCID: PMC9499886 DOI: 10.1007/s10856-022-06690-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 08/27/2022] [Indexed: 06/16/2023]
Abstract
Polydimethylsiloxane (PDMS) is a commonly used insulation/packaging material for implantable neural electrodes. Nevertheless, the PDMS-initiated tissue response would lead to the deterioration of the electrode performances post-implantation, owing to its intrinsic hydrophobic and cell-repellent surface. The conventional physical coatings by hydrophilic hydrogels or bioactive molecules are unable to maintain during the long-term implantation due to their low stability by physical adhesion. In this work, we first anchor both hydrophilic polyethylene glycol (PEG) and bioactive molecule poly-L-lysine (PLL) on the PDMS surface by chemical coupling to change the PDMS surface from hydrophobic and cell-repellent to hydrophilic and cell-adhesive. XPS tests indicate the chemically coupled modification layers are stable on the PDMS surface after experiencing a harsh rinse process. Contact angle measurements show that the use of PEG 600 with the moderate molecular weight results in the highest hydrophilicity for the resulting PDMS-PEG-PLL. PC12 cell evaluation results exhibit that the PDMS-PEG-PLL with PEG 600 leads to significantly larger cell adhesion area, more neurite number, and longer neurite length than the PDMS. The PDMS-PEG-PLL with PEG 600 featuring stable modification layers, high hydrophilicity, and superior cell affinity has great potential in stabilizing the neural electrode-tissue interface for the long-term implantation. Graphical abstract.
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Affiliation(s)
- Li Rao
- Department of Geriatrics, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Yuqin Liu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China
| | - Haihan Zhou
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan, 030006, China.
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13
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Amini S, Seche W, May N, Choi H, Tavousi P, Shahbazmohamadi S. Femtosecond laser hierarchical surface restructuring for next generation neural interfacing electrodes and microelectrode arrays. Sci Rep 2022; 12:13966. [PMID: 35978090 PMCID: PMC9385846 DOI: 10.1038/s41598-022-18161-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 08/05/2022] [Indexed: 11/09/2022] Open
Abstract
Long-term implantable neural interfacing devices are able to diagnose, monitor, and treat many cardiac, neurological, retinal and hearing disorders through nerve stimulation, as well as sensing and recording electrical signals to and from neural tissue. To improve specificity, functionality, and performance of these devices, the electrodes and microelectrode arrays-that are the basis of most emerging devices-must be further miniaturized and must possess exceptional electrochemical performance and charge exchange characteristics with neural tissue. In this report, we show for the first time that the electrochemical performance of femtosecond-laser hierarchically-restructured electrodes can be tuned to yield unprecedented performance values that significantly exceed those reported in the literature, e.g. charge storage capacity and specific capacitance were shown to have improved by two orders of magnitude and over 700-fold, respectively, compared to un-restructured electrodes. Additionally, correlation amongst laser parameters, electrochemical performance and surface parameters of the electrodes was established, and while performance metrics exhibit a relatively consistent increasing behavior with laser parameters, surface parameters tend to follow a less predictable trend negating a direct relationship between these surface parameters and performance. To answer the question of what drives such performance and tunability, and whether the widely adopted reasoning of increased surface area and roughening of the electrodes are the key contributors to the observed increase in performance, cross-sectional analysis of the electrodes using focused ion beam shows, for the first time, the existence of subsurface features that may have contributed to the observed electrochemical performance enhancements. This report is the first time that such performance enhancement and tunability are reported for femtosecond-laser hierarchically-restructured electrodes for neural interfacing applications.
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Affiliation(s)
- Shahram Amini
- Research and Development, Pulse Technologies Inc., Quakertown, PA, 18951, USA. .,Biomedical Engineering Department, University of Connecticut, Storrs, CT, 06269, USA.
| | - Wesley Seche
- Research and Development, Pulse Technologies Inc., Quakertown, PA, 18951, USA
| | - Nicholas May
- Biomedical Engineering Department, University of Connecticut, Storrs, CT, 06269, USA
| | - Hongbin Choi
- Biomedical Engineering Department, University of Connecticut, Storrs, CT, 06269, USA
| | - Pouya Tavousi
- UConn Tech Park, University of Connecticut, Storrs, CT, 06269, USA
| | - Sina Shahbazmohamadi
- Biomedical Engineering Department, University of Connecticut, Storrs, CT, 06269, USA
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14
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Murphy BB, Apollo NV, Unegbu P, Posey T, Rodriguez-Perez N, Hendricks Q, Cimino F, Richardson AG, Vitale F. Vitamin C-reduced graphene oxide improves the performance and stability of multimodal neural microelectrodes. iScience 2022; 25:104652. [PMID: 35811842 PMCID: PMC9263525 DOI: 10.1016/j.isci.2022.104652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/28/2022] [Accepted: 06/16/2022] [Indexed: 11/28/2022] Open
Abstract
Nanocarbons are often employed as coatings for neural electrodes to enhance surface area. However, processing and integrating them into microfabrication flows requires complex and harmful chemical and heating conditions. This article presents a safe, scalable, cost-effective method to produce reduced graphene oxide (rGO) coatings using vitamin C (VC) as the reducing agent. We spray coat GO + VC mixtures onto target substrates, and then heat samples for 15 min at 150°C. The resulting rGO films have conductivities of ∼44 S cm−1, and are easily integrated into an ad hoc microfabrication flow. The rGO/Au microelectrodes show ∼8x lower impedance and ∼400x higher capacitance than bare Au, resulting in significantly enhanced charge storage and injection capacity. We subsequently use rGO/Au arrays to detect dopamine in vitro, and to map cortical activity intraoperatively over rat whisker barrel cortex, demonstrating that conductive VC-rGO coatings improve the performance and stability of multimodal microelectrodes for different applications. Easy, scalable, and safe reduction method to create rGO films with vitamin C VC-rGO coatings improve the performance of bare gold microelectrodes in vitro VC-rGO coatings enable the voltammetric detection of dopamine on the microscale rGO/Au electrode arrays enable high-resolution microscale recording in vivo
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Affiliation(s)
- Brendan B. Murphy
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Nicholas V. Apollo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Placid Unegbu
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Tessa Posey
- Department of Biomedical Engineering, University of South Carolina, Columbia, SC 29206, USA
| | - Nancy Rodriguez-Perez
- School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ 85281, USA
| | - Quincy Hendricks
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Francesca Cimino
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrew G. Richardson
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Flavia Vitale
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
- Department of Physical Medicine and Rehabilitation, University of Pennsylvania, Philadelphia, PA 19146, USA
- Corresponding author
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15
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Redolfi Riva E, D’Alessio A, Micera S. Polysaccharide Layer-by-Layer Coating for Polyimide-Based Neural Interfaces. MICROMACHINES 2022; 13:mi13050692. [PMID: 35630159 PMCID: PMC9146946 DOI: 10.3390/mi13050692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/19/2022] [Accepted: 04/27/2022] [Indexed: 02/01/2023]
Abstract
Implantable flexible neural interfaces (IfNIs) are capable of directly modulating signals of the central and peripheral nervous system by stimulating or recording the action potential. Despite outstanding results in acute experiments on animals and humans, their long-term biocompatibility is hampered by the effects of foreign body reactions that worsen electrical performance and cause tissue damage. We report on the fabrication of a polysaccharide nanostructured thin film as a coating of polyimide (PI)-based IfNIs. The layer-by-layer technique was used to coat the PI surface due to its versatility and ease of manufacturing. Two different LbL deposition techniques were tested and compared: dip coating and spin coating. Morphological and physiochemical characterization showed the presence of a very smooth and nanostructured thin film coating on the PI surface that remarkably enhanced surface hydrophilicity with respect to the bare PI surface for both the deposition techniques. However, spin coating offered more control over the fabrication properties, with the possibility to tune the coating’s physiochemical and morphological properties. Overall, the proposed coating strategies allowed the deposition of a biocompatible nanostructured film onto the PI surface and could represent a valid tool to enhance long-term IfNI biocompatibility by improving tissue/electrode integration.
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Affiliation(s)
- Eugenio Redolfi Riva
- The BioRobotics Institute, Department of Excellence in Robotics and AI, Scuola Superiore Sant’Anna, 56127 Pisa, Italy; (A.D.); (S.M.)
- Correspondence:
| | - Angela D’Alessio
- The BioRobotics Institute, Department of Excellence in Robotics and AI, Scuola Superiore Sant’Anna, 56127 Pisa, Italy; (A.D.); (S.M.)
| | - Silvestro Micera
- The BioRobotics Institute, Department of Excellence in Robotics and AI, Scuola Superiore Sant’Anna, 56127 Pisa, Italy; (A.D.); (S.M.)
- Translational Neuroengineering, Centre for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1000 Lausanne, Switzerland
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16
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Manousiouthakis E, Park J, Hardy JG, Lee JY, Schmidt CE. Towards the translation of electroconductive organic materials for regeneration of neural tissues. Acta Biomater 2022; 139:22-42. [PMID: 34339871 DOI: 10.1016/j.actbio.2021.07.065] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/23/2021] [Accepted: 07/27/2021] [Indexed: 12/13/2022]
Abstract
Carbon-based conductive and electroactive materials (e.g., derivatives of graphene, fullerenes, polypyrrole, polythiophene, polyaniline) have been studied since the 1970s for use in a broad range of applications. These materials have electrical properties comparable to those of commonly used metals, while providing other benefits such as flexibility in processing and modification with biologics (e.g., cells, biomolecules), to yield electroactive materials with biomimetic mechanical and chemical properties. In this review, we focus on the uses of these electroconductive materials in the context of the central and peripheral nervous system, specifically recent studies in the peripheral nerve, spinal cord, brain, eye, and ear. We also highlight in vivo studies and clinical trials, as well as a snapshot of emerging classes of electroconductive materials (e.g., biodegradable materials). We believe such specialized electrically conductive biomaterials will clinically impact the field of tissue regeneration in the foreseeable future. STATEMENT OF SIGNIFICANCE: This review addresses the use of conductive and electroactive materials for neural tissue regeneration, which is of significant interest to a broad readership, and of particular relevance to the growing community of scientists, engineers and clinicians in academia and industry who develop novel medical devices for tissue engineering and regenerative medicine. The review covers the materials that may be employed (primarily focusing on derivatives of fullerenes, graphene and conjugated polymers) and techniques used to analyze materials composed thereof, followed by sections on the application of these materials to nervous tissues (i.e., peripheral nerve, spinal cord, brain, optical, and auditory tissues) throughout the body.
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Affiliation(s)
- Eleana Manousiouthakis
- Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville 32611, FL, United States
| | - Junggeon Park
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - John G Hardy
- Department of Chemistry, Lancaster University, Lancaster LA1 4YB, United Kingdom; Materials Science Institute, Lancaster University, Lancaster LA1 4YB, United Kingdom.
| | - Jae Young Lee
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
| | - Christine E Schmidt
- Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville 32611, FL, United States.
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17
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Oldroyd P, Malliaras GG. Achieving long-term stability of thin-film electrodes for neurostimulation. Acta Biomater 2022; 139:65-81. [PMID: 34020055 DOI: 10.1016/j.actbio.2021.05.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/06/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022]
Abstract
Implantable electrodes that can reliably measure brain activity and deliver an electrical stimulus to a target tissue are increasingly employed to treat various neurological diseases and neuropsychiatric disorders. Flexible thin-film electrodes have gained attention over the past few years to minimise invasiveness and damage upon implantation. Research has previously focused on optimising the electrode's electrical and mechanical properties; however, their chronic stability must be validated to translate electrodes from a research to a clinical application. Neurostimulation electrodes, which actively inject charge, have yet to reliably demonstrate continuous functionality for ten years or more in vivo, the accepted metric for clinical viability. Long-term stability can only be achieved if the focus switches to investigating how and why such devices fail. Unfortunately, there is a field-wide reluctance to investigate device stability and failures, which hinders device optimisation. This review surveys thin-film electrode designs with a focus on adhesion between electrode layers and the interactions with the surrounding environment. A comprehensive summary of the abiotic failure modes faced by such electrodes is presented, and to encourage investigation, systematic methods for analysing their origin are recommended. Finally, approaches to reducing the likelihood of device failure are offered. STATEMENT OF SIGNIFICANCE: Neural electrodes that can deliver an electrical stimulus to a target tissue are widely used to treat various neurological diseases. Essential to the function of these electrodes is the ability to safely stimulate the target tissue for extended periods (> 10 years); however, this has not yet been clinically achieved. The key to achieving long-term stability is an increased understanding of electrode interactions with the surrounding tissue and subsequent systematic analysis of their failure modes. This review highlights the need for a change in the approach to investigating electrode failure, and in doing so summarizes the common ways in which neural electrodes fail, methods for identifying them and approaches to preventing them.
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18
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Abstract
![]()
Electronically interfacing with the
nervous system for the purposes
of health diagnostics and therapy, sports performance monitoring,
or device control has been a subject of intense academic and industrial
research for decades. This trend has only increased in recent years,
with numerous high-profile research initiatives and commercial endeavors.
An important research theme has emerged as a result, which is the
incorporation of semiconducting polymers in various devices that communicate
with the nervous system—from wearable brain-monitoring caps
to penetrating implantable microelectrodes. This has been driven by
the potential of this broad class of materials to improve the electrical
and mechanical properties of the tissue–device interface, along
with possibilities for increased biocompatibility. In this review
we first begin with a tutorial on neural interfacing, by reviewing
the basics of nervous system function, device physics, and neuroelectrophysiological
techniques and their demands, and finally we give a brief perspective
on how material improvements can address current deficiencies in this
system. The second part is a detailed review of past work on semiconducting
polymers, covering electrical properties, structure, synthesis, and
processing.
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Affiliation(s)
- Ivan B Dimov
- Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, U.K
| | - Maximilian Moser
- University of Oxford, Department of Chemistry, Oxford OX1 3TA, United Kingdom
| | - George G Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, U.K
| | - Iain McCulloch
- University of Oxford, Department of Chemistry, Oxford OX1 3TA, United Kingdom.,King Abdullah University of Science and Technology (KAUST), KAUST Solar Center, Thuwal 23955-6900, Saudi Arabia
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19
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Vėbraitė I, Hanein Y. Soft Devices for High-Resolution Neuro-Stimulation: The Interplay Between Low-Rigidity and Resolution. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:675744. [PMID: 35047928 PMCID: PMC8757739 DOI: 10.3389/fmedt.2021.675744] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/14/2021] [Indexed: 12/27/2022] Open
Abstract
The field of neurostimulation has evolved over the last few decades from a crude, low-resolution approach to a highly sophisticated methodology entailing the use of state-of-the-art technologies. Neurostimulation has been tested for a growing number of neurological applications, demonstrating great promise and attracting growing attention in both academia and industry. Despite tremendous progress, long-term stability of the implants, their large dimensions, their rigidity and the methods of their introduction and anchoring to sensitive neural tissue remain challenging. The purpose of this review is to provide a concise introduction to the field of high-resolution neurostimulation from a technological perspective and to focus on opportunities stemming from developments in materials sciences and engineering to reduce device rigidity while optimizing electrode small dimensions. We discuss how these factors may contribute to smaller, lighter, softer and higher electrode density devices.
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Affiliation(s)
- Ieva Vėbraitė
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yael Hanein
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
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20
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Berggren M, Głowacki ED, Simon DT, Stavrinidou E, Tybrandt K. In Vivo Organic Bioelectronics for Neuromodulation. Chem Rev 2022; 122:4826-4846. [PMID: 35050623 PMCID: PMC8874920 DOI: 10.1021/acs.chemrev.1c00390] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
![]()
The nervous system
poses a grand challenge for integration with
modern electronics and the subsequent advances in neurobiology, neuroprosthetics,
and therapy which would become possible upon such integration. Due
to its extreme complexity, multifaceted signaling pathways, and ∼1
kHz operating frequency, modern complementary metal oxide semiconductor
(CMOS) based electronics appear to be the only technology platform
at hand for such integration. However, conventional CMOS-based electronics
rely exclusively on electronic signaling and therefore require an
additional technology platform to translate electronic signals into
the language of neurobiology. Organic electronics are just such a
technology platform, capable of converting electronic addressing into
a variety of signals matching the endogenous signaling of the nervous
system while simultaneously possessing favorable material similarities
with nervous tissue. In this review, we introduce a variety of organic
material platforms and signaling modalities specifically designed
for this role as “translator”, focusing especially on
recent implementation in in vivo neuromodulation.
We hope that this review serves both as an informational resource
and as an encouragement and challenge to the field.
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Affiliation(s)
- Magnus Berggren
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 601 74 Norrköping, Sweden
| | - Eric D Głowacki
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 601 74 Norrköping, Sweden.,Bioelectronics Materials and Devices, Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 612 00 Brno, Czech Republic
| | - Daniel T Simon
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 601 74 Norrköping, Sweden
| | - Eleni Stavrinidou
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 601 74 Norrköping, Sweden
| | - Klas Tybrandt
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, 601 74 Norrköping, Sweden
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21
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Green RA. Possibilities in bioelectronics: Super humans or science fiction? APL Bioeng 2021; 5:040401. [PMID: 34964001 DOI: 10.1063/5.0079530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/08/2021] [Indexed: 12/16/2022] Open
Abstract
Recent years have led to a rapid increase in the development of neurotechnologies for diagnosis, monitoring, and treatment of conditions with neurological targets. The central driving force has been the need for next-generation devices to treat neural injury and disease, where current pharmaceutical or conventional bioelectronics have been unable to impart sufficient therapeutic effects. The advent of new therapies and advanced technologies has resulted in a reemergence of the concept of superhuman performance. This is a hypothetical possibility that is enabled when bionics are used to augment the neural system and has included the notions of improved cognitive ability and enhancement of hearing and seeing beyond the limitations of a healthy human. It is quite conceivable that a bionic eye could be used for night vision; however, the damage to both the neural system and surrounding tissues in placing such a device is only considered acceptable in the case of a patient that can obtain improvement in quality of life. There are also critical limitations that have hindered clinical translation of high-resolution neural interfaces, despite significant advances in biomaterial and bioelectronics technologies, including the advent of biohybrid devices. Surgical damage and foreign body reactions to such devices can be reduced but not eliminated, and these engineering solutions to reduce inflammation present additional challenges to the long-term performance and medical regulation. As a result, while bioelectronics has seen concepts from science fiction realized, there remains a significant gap to their use as enhancements beyond medical therapies.
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Affiliation(s)
- Rylie A Green
- Department of Bioengineering, Imperial College London, London SW7 2AS, United Kingdom
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22
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Thakur R, Aplin FP, Fridman GY. A Hydrogel-Based Microfluidic Nerve Cuff for Neuromodulation of Peripheral Nerves. MICROMACHINES 2021; 12:mi12121522. [PMID: 34945372 PMCID: PMC8706247 DOI: 10.3390/mi12121522] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/22/2021] [Accepted: 12/03/2021] [Indexed: 11/16/2022]
Abstract
Implantable neuromodulation devices typically have metal in contact with soft, ion-conducting nerves. These neural interfaces excite neurons using short-duration electrical pulses. While this approach has been extremely successful for multiple clinical applications, it is limited in delivering long-duration pulses or direct current (DC), even for acute term studies. When the charge injection capacity of electrodes is exceeded, irreversible electrochemical processes occur, and toxic byproducts are discharged directly onto the nerve, causing biological damage. Hydrogel coatings on electrodes improve the overall charge injection limit and provide a mechanically pliable interface. To further extend this idea, we developed a silicone-based nerve cuff lead with a hydrogel microfluidic conduit. It serves as a thin, soft and flexible interconnection and provides a greater spatial separation between metal electrodes and the target nerve. In an in vivo rat model, we used this cuff to stimulate and record from sciatic nerves, with performance comparable to that of metal electrodes. Further, we delivered DC through the lead in an acute manner to induce nerve block that is reversible. In contrast to most metallic cuff electrodes, which need microfabrication equipment, we built this cuff using a consumer-grade digital cutter and a simplified molding process. Overall, the device will be beneficial to neuromodulation researchers as a general-purpose nerve cuff electrode for peripheral neuromodulation experiments.
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Affiliation(s)
- Raviraj Thakur
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University, Baltimore, MD 21205, USA; (R.T.); (F.P.A.)
| | - Felix P. Aplin
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University, Baltimore, MD 21205, USA; (R.T.); (F.P.A.)
| | - Gene Y. Fridman
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University, Baltimore, MD 21205, USA; (R.T.); (F.P.A.)
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- Correspondence:
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23
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Shi D, Dhawan V, Cui XT. Bio-integrative design of the neural tissue-device interface. Curr Opin Biotechnol 2021; 72:54-61. [PMID: 34710753 PMCID: PMC8671324 DOI: 10.1016/j.copbio.2021.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 09/19/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022]
Abstract
Neural implants enable bidirectional communications with nervous tissue and have demonstrated tremendous potential in research and clinical applications. To obtain high fidelity and stable information exchange, we need to minimize the undesired host responses and achieve intimate neuron-device interaction. This paper highlights the key bio-integrative strategies aimed at seamless integration through intelligent device designs to minimize the immune responses, as well as incorporate bioactive elements to actively modulate cellular reactions. These approaches span from surface modification and bioactive agent delivery, to biomorphic and biohybrid designs. Many of these strategies have shown effectiveness in functional outcome measures, others are exploratory but with fascinating potentials. The combination of bio-integrative strategies may synergistically promote the next generation of neural interfaces.
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Affiliation(s)
- Delin Shi
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Center for Neural Basis of Cognition, Pittsburgh, PA, United States
| | - Vaishnavi Dhawan
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Center for Neural Basis of Cognition, Pittsburgh, PA, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; Center for Neural Basis of Cognition, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, Pittsburgh, PA, United States.
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24
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Kilias A, Lee YT, Froriep UP, Sielaff C, Moser D, Holzhammer T, Egert U, Fang W, Paul O, Ruther P. Intracortical probe arrays with silicon backbone and microelectrodes on thin polyimide wings enable long-term stable recordings in vivo. J Neural Eng 2021; 18. [PMID: 34781276 DOI: 10.1088/1741-2552/ac39b7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 11/15/2021] [Indexed: 11/12/2022]
Abstract
Objective.Recording and stimulating neuronal activity across different brain regions requires interfacing at multiple sites using dedicated tools while tissue reactions at the recording sites often prevent their successful long-term application. This implies the technological challenge of developing complex probe geometries while keeping the overall footprint minimal, and of selecting materials compatible with neural tissue. While the potential of soft materials in reducing tissue response is uncontested, the implantation of these materials is often limited to reliably target neuronal structures across large brain volumes.Approach.We report on the development of a new multi-electrode array exploiting the advantages of soft and stiff materials by combining 7-µm-thin polyimide wings carrying platinum electrodes with a silicon backbone enabling a safe probe implantation. The probe fabrication applies microsystems technologies in combination with a temporal wafer fixation method for rear side processing, i.e. grinding and deep reactive ion etching, of slender probe shanks and electrode wings. The wing-type neural probes are chronically implanted into the entorhinal-hippocampal formation in the mouse forin vivorecordings of freely behaving animals.Main results.Probes comprising the novel wing-type electrodes have been realized and characterized in view of their electrical performance and insertion capability. Chronic electrophysiologicalin vivorecordings of the entorhinal-hippocampal network in the mouse of up to 104 days demonstrated a stable yield of channels containing identifiable multi-unit and single-unit activity outperforming probes with electrodes residing on a Si backbone.Significance.The innovative fabrication process using a process compatible, temporary wafer bonding allowed to realize new Michigan-style probe arrays. The wing-type probe design enables a precise probe insertion into brain tissue and long-term stable recordings of unit activity due to the application of a stable backbone and 7-µm-thin probe wings provoking locally a minimal tissue response and protruding from the glial scare of the backbone.
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Affiliation(s)
- Antje Kilias
- Biomicrotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Yu-Tao Lee
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Institute of NanoEngineering and Microsystems, National Tsing-Hua University, Hsinchu, Taiwan
| | - Ulrich P Froriep
- Biomicrotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany.,Department of Implant Systems, Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Hannover, Germany
| | - Charlotte Sielaff
- Department of Implant Systems, Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Hannover, Germany
| | - Dominik Moser
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Tobias Holzhammer
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany
| | - Ulrich Egert
- Biomicrotechnology, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany.,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
| | - Weileun Fang
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu City, Taiwan
| | - Oliver Paul
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
| | - Patrick Ruther
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
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25
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Hyakumura T, Aregueta-Robles U, Duan W, Villalobos J, Adams WK, Poole-Warren L, Fallon JB. Improving Deep Brain Stimulation Electrode Performance in vivo Through Use of Conductive Hydrogel Coatings. Front Neurosci 2021; 15:761525. [PMID: 34803592 PMCID: PMC8602793 DOI: 10.3389/fnins.2021.761525] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/11/2021] [Indexed: 11/13/2022] Open
Abstract
Active implantable neurological devices like deep brain stimulators have been used over the past few decades to treat movement disorders such as those in people with Parkinson’s disease and more recently, in psychiatric conditions like obsessive compulsive disorder. Electrode-tissue interfaces that support safe and effective targeting of specific brain regions are critical to success of these devices. Development of directional electrodes that activate smaller volumes of brain tissue requires electrodes to operate safely with higher charge densities. Coatings such as conductive hydrogels (CHs) provide lower impedances and higher charge injection limits (CILs) than standard platinum electrodes and support safer application of smaller electrode sizes. The aim of this study was to examine the chronic in vivo performance of a new low swelling CH coating that supports higher safe charge densities than traditional platinum electrodes. A range of hydrogel blends were engineered and their swelling and electrical performance compared. Electrochemical performance and stability of high and low swelling formulations were compared during insertion into a model brain in vitro and the formulation with lower swelling characteristics was chosen for the in vivo study. CH-coated or uncoated Pt electrode arrays were implanted into the brains of 14 rats, and their electrochemical performance was tested weekly for 8 weeks. Tissue response and neural survival was assessed histologically following electrode array removal. CH coating resulted in significantly lower voltage transient impedance, higher CIL, lower electrochemical impedance spectroscopy, and higher charge storage capacity compared to uncoated Pt electrodes in vivo, and this advantage was maintained over the 8-week implantation. There was no significant difference in evoked potential thresholds, signal-to-noise ratio, tissue response or neural survival between CH-coated and uncoated Pt groups. The significant electrochemical advantage and stability of CH coating in the brain supports the suitability of this coating technology for future development of smaller, higher fidelity electrode arrays with higher charge density requirement.
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Affiliation(s)
- Tomoko Hyakumura
- The Bionics Institute of Australia, East Melbourne, VIC, Australia.,Department of Medical Bionics, The University of Melbourne, Parkville, VIC, Australia
| | - Ulises Aregueta-Robles
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW, Australia
| | - Wenlu Duan
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW, Australia
| | - Joel Villalobos
- The Bionics Institute of Australia, East Melbourne, VIC, Australia.,Department of Medical Bionics, The University of Melbourne, Parkville, VIC, Australia
| | - Wendy K Adams
- The Bionics Institute of Australia, East Melbourne, VIC, Australia
| | - Laura Poole-Warren
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW, Australia.,Tyree Foundation Institute of Health Engineering, The University of New South Wales, Sydney, NSW, Australia
| | - James B Fallon
- The Bionics Institute of Australia, East Melbourne, VIC, Australia.,Department of Medical Bionics, The University of Melbourne, Parkville, VIC, Australia
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26
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Richter B, Mace Z, Hays ME, Adhikari S, Pham HQ, Sclabassi RJ, Kolber B, Yerneni SS, Campbell P, Cheng B, Tomycz N, Whiting DM, Le TQ, Nelson TL, Averick S. Development and Characterization of Novel Conductive Sensing Fibers for In Vivo Nerve Stimulation. SENSORS (BASEL, SWITZERLAND) 2021; 21:7581. [PMID: 34833660 PMCID: PMC8619502 DOI: 10.3390/s21227581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 11/03/2021] [Accepted: 11/07/2021] [Indexed: 12/11/2022]
Abstract
Advancements in electrode technologies to both stimulate and record the central nervous system's electrical activities are enabling significant improvements in both the understanding and treatment of different neurological diseases. However, the current neural recording and stimulating electrodes are metallic, requiring invasive and damaging methods to interface with neural tissue. These electrodes may also degrade, resulting in additional invasive procedures. Furthermore, metal electrodes may cause nerve damage due to their inherent rigidity. This paper demonstrates that novel electrically conductive organic fibers (ECFs) can be used for direct nerve stimulation. The ECFs were prepared using a standard polyester material as the structural base, with a carbon nanotube ink applied to the surface as the electrical conductor. We report on three experiments: the first one to characterize the conductive properties of the ECFs; the second one to investigate the fiber cytotoxic properties in vitro; and the third one to demonstrate the utility of the ECF for direct nerve stimulation in an in vivo rodent model.
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Affiliation(s)
- Bertram Richter
- System Department of Neurosurgery, Allegheny Health Network, Pittsburgh, PA 15212, USA; (B.R.); (Z.M.); (R.J.S.); (B.C.); (N.T.); (D.M.W.)
| | - Zachary Mace
- System Department of Neurosurgery, Allegheny Health Network, Pittsburgh, PA 15212, USA; (B.R.); (Z.M.); (R.J.S.); (B.C.); (N.T.); (D.M.W.)
- Computational Diagnostics, Inc., Pittsburgh, PA 15213, USA
| | - Megan E. Hays
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA; (M.E.H.); (S.A.); (T.L.N.)
| | - Santosh Adhikari
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA; (M.E.H.); (S.A.); (T.L.N.)
| | - Huy Q. Pham
- Department of Biomedical Engineering, North Dakota State University, Fargo, ND 58102, USA;
| | - Robert J. Sclabassi
- System Department of Neurosurgery, Allegheny Health Network, Pittsburgh, PA 15212, USA; (B.R.); (Z.M.); (R.J.S.); (B.C.); (N.T.); (D.M.W.)
- Computational Diagnostics, Inc., Pittsburgh, PA 15213, USA
| | - Benedict Kolber
- Department of Neuroscience, University of Texas at Dallas, Richardson, TX 75080, USA;
| | - Saigopalakrishna S. Yerneni
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15217, USA; (S.S.Y.); (P.C.)
| | - Phil Campbell
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15217, USA; (S.S.Y.); (P.C.)
| | - Boyle Cheng
- System Department of Neurosurgery, Allegheny Health Network, Pittsburgh, PA 15212, USA; (B.R.); (Z.M.); (R.J.S.); (B.C.); (N.T.); (D.M.W.)
| | - Nestor Tomycz
- System Department of Neurosurgery, Allegheny Health Network, Pittsburgh, PA 15212, USA; (B.R.); (Z.M.); (R.J.S.); (B.C.); (N.T.); (D.M.W.)
| | - Donald M. Whiting
- System Department of Neurosurgery, Allegheny Health Network, Pittsburgh, PA 15212, USA; (B.R.); (Z.M.); (R.J.S.); (B.C.); (N.T.); (D.M.W.)
| | - Trung Q. Le
- Department of Industrial and Manufacturing Engineering, North Dakota State University, Fargo, ND 58102, USA
| | - Toby L. Nelson
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA; (M.E.H.); (S.A.); (T.L.N.)
| | - Saadyah Averick
- System Department of Neurosurgery, Allegheny Health Network, Pittsburgh, PA 15212, USA; (B.R.); (Z.M.); (R.J.S.); (B.C.); (N.T.); (D.M.W.)
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27
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Cheedarala RK, Chalapathi KV, Song JI. Delayed Flammability for Natural Fabrics by Deposition of Silica Core-Amine Shell Microspheres through Dip-Coating Process. CHEMICAL ENGINEERING JOURNAL ADVANCES 2021. [DOI: 10.1016/j.ceja.2021.100164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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28
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Portillo-Lara R, Goding JA, Green RA. Adaptive biomimicry: design of neural interfaces with enhanced biointegration. Curr Opin Biotechnol 2021; 72:62-68. [PMID: 34715548 DOI: 10.1016/j.copbio.2021.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 10/01/2021] [Accepted: 10/06/2021] [Indexed: 12/27/2022]
Abstract
Neural interfaces (NIs) have traditionally used inorganic device constructs paired with electrical stimulation to bypass injured or diseased electroactive tissues. These bioinert devices have significant impact on the neural tissue, being synthetic and causing large volumetric changes to the biological environment. The concept of biomimicry has become popular for tissue engineering technologies, reflecting biological properties as a component of material design. Tissue engineering strategies can be harnessed in bioelectronic device design to improve biological tolerance, but the need for improved integration with the native tissue remains an unmet need. Adaptive biomimetic designs that respond to the changing neural tissue environment associated with wound healing can actively address the immune response to improve biointegration. These adaptive approaches include responsive materials paired with stem cells and bioactive molecules as integrated components of NIs. Combining adaptive biomimetics with NIs provides a new, more natural approach for communicating with the nervous system.
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Affiliation(s)
- Roberto Portillo-Lara
- Department of Bioengineering, Imperial College London, SW7 2BP, London, United Kingdom
| | - Josef A Goding
- Department of Bioengineering, Imperial College London, SW7 2BP, London, United Kingdom
| | - Rylie A Green
- Department of Bioengineering, Imperial College London, SW7 2BP, London, United Kingdom.
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29
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Wei W, Wang X. Graphene-Based Electrode Materials for Neural Activity Detection. MATERIALS (BASEL, SWITZERLAND) 2021; 14:6170. [PMID: 34683762 PMCID: PMC8539724 DOI: 10.3390/ma14206170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/07/2021] [Accepted: 10/11/2021] [Indexed: 12/17/2022]
Abstract
The neural electrode technique is a powerful tool for monitoring and regulating neural activity, which has a wide range of applications in basic neuroscience and the treatment of neurological diseases. Constructing a high-performance electrode-nerve interface is required for the long-term stable detection of neural signals by electrodes. However, conventional neural electrodes are mainly fabricated from rigid materials that do not match the mechanical properties of soft neural tissues, thus limiting the high-quality recording of neuroelectric signals. Meanwhile, graphene-based nanomaterials can form stable electrode-nerve interfaces due to their high conductivity, excellent flexibility, and biocompatibility. In this literature review, we describe various graphene-based electrodes and their potential application in neural activity detection. We also discuss the biological safety of graphene neural electrodes, related challenges, and their prospects.
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Affiliation(s)
- Weichen Wei
- Materials Science and Engineering Program, University of California San Diego, La Jolla, CA 92093, USA;
| | - Xuejiao Wang
- Fujian Provincial University Engineering Research Center of Industrial Biocatalysis, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007, China
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30
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Fan B, Wolfrum B, Robinson JT. Impedance scaling for gold and platinum microelectrodes. J Neural Eng 2021; 18. [PMID: 34433150 DOI: 10.1088/1741-2552/ac20e5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/25/2021] [Indexed: 11/11/2022]
Abstract
Objective.Electrical measurement of the activity of individual neurons is a primary goal for many invasive neural electrodes. Making these 'single unit' measurements requires that we fabricate electrodes small enough so that only a few neurons contribute to the signal, but not so small that the impedance of the electrode creates overwhelming noise or signal attenuation. Thus, neuroelectrode design often must strike a balance between electrode size and electrode impedance, where the impedance is often assumed to scale linearly with electrode area.Approach and main results. Here we study how impedance scales with neural electrode area and find that the 1 kHz impedance of Pt electrodes (but not Au electrodes) transitions from scaling with area (r-2) to scaling with perimeter (r-1) when the electrode radius falls below 10µm. This effect can be explained by the transition from planar to spherical diffusion behavior previously reported for electrochemical microelectrodes.Significance.These results provide important intuition for designing small, single unit recording electrodes. Specifically, for materials where the impedance is dominated by a pseudo-capacitance that is associated with a diffusion limited process, the total impedance will scale with perimeter rather than area when the electrode size becomes comparable with the diffusion layer thickness. For Pt electrodes this transition occurs around 10µm radius electrodes. At even lower frequencies (1 Hz) impedance approaches a constant. This transition tor-1scaling implies that electrodes with a pseudo-capacitance can be made smaller than one might expect before thermal noise or voltage division limits the ability to acquire high-quality single-unit recordings.
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Affiliation(s)
- Bo Fan
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, United States of America
| | - Bernhard Wolfrum
- Department of Electrical and Computer Engineering, Technical University of Munich, Garching, 85748, Germany
| | - Jacob T Robinson
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, United States of America.,Department of Bioengineering, Rice University, Houston, TX 77005, United States of America.,Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, United States of America
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31
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Kim D, Park D, Kim TH, Chung JJ, Jung Y, Kim SH. Substance P/Heparin-Conjugated PLCL Mitigate Acute Gliosis on Neural Implants and Improve Neuronal Regeneration via Recruitment of Neural Stem Cells. Adv Healthc Mater 2021; 10:e2100107. [PMID: 34227258 DOI: 10.1002/adhm.202100107] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/03/2021] [Indexed: 12/15/2022]
Abstract
The inflammatory host tissue response, characterized by gliosis and neuronal death at the neural interface, limits signal transmission and longevity of the neural probe. Substance P induces an anti-inflammatory response and neuronal regeneration and recruits endogenous stem cells. Heparin prevents nonspecific protein adsorption, suppresses the inflammatory response, and is beneficial to neuronal behavior. Poly(l-lactide-co-ε-caprolactone) (PLCL) is a soft and flexible polymer, and PLCL covalently conjugated with biomolecules has been widely used in tissue engineering. Coatings of heparin-conjugated PLCL (Hep-PLCL), substance P-conjugated PLCL (SP-PLCL), and heparin/substance P-conjugated PLCL (Hep/SP-PLCL) reduced the adhesion of astrocytes and fibroblasts and improved neuronal adhesion and neurite development compared to bare glass. The effects of these coatings are evaluated using immunohistochemistry analysis after implantation of coated stainless steel probes in rat brain for 1 week. In particular, Hep/SP-PLCL coating reduced the activation of microglia and astrocytes, the neuronal degeneration caused by inflammation, and indicated a potential for neuronal regeneration at the tissue-device interface. Suppression of the acute host tissue response by coating Hep/SP-PLCL could lead to improved functionality of the neural prosthesis.
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Affiliation(s)
- Donghak Kim
- KU‐KIST Graduate School of Converging Science and Technology Korea University 145 Anam‐ro, Seongbuk‐gu Seoul 02841 Republic of Korea
- Biomaterials Research Center Korea Institute of Science and Technology (KIST) 5, Hwarang‐ro 14‐gil, Seongbuk‐gu Seoul 02792 Republic of Korea
| | - DoYeun Park
- Biomaterials Research Center Korea Institute of Science and Technology (KIST) 5, Hwarang‐ro 14‐gil, Seongbuk‐gu Seoul 02792 Republic of Korea
| | - Tae Hee Kim
- Biomaterials Research Center Korea Institute of Science and Technology (KIST) 5, Hwarang‐ro 14‐gil, Seongbuk‐gu Seoul 02792 Republic of Korea
| | - Justin J. Chung
- Biomaterials Research Center Korea Institute of Science and Technology (KIST) 5, Hwarang‐ro 14‐gil, Seongbuk‐gu Seoul 02792 Republic of Korea
| | - Youngmee Jung
- Biomaterials Research Center Korea Institute of Science and Technology (KIST) 5, Hwarang‐ro 14‐gil, Seongbuk‐gu Seoul 02792 Republic of Korea
| | - Soo Hyun Kim
- KU‐KIST Graduate School of Converging Science and Technology Korea University 145 Anam‐ro, Seongbuk‐gu Seoul 02841 Republic of Korea
- Biomaterials Research Center Korea Institute of Science and Technology (KIST) 5, Hwarang‐ro 14‐gil, Seongbuk‐gu Seoul 02792 Republic of Korea
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32
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Fabrication of Soft Tissue Scaffold-Mimicked Microelectrode Arrays Using Enzyme-Mediated Transfer Printing. MICROMACHINES 2021; 12:mi12091057. [PMID: 34577700 PMCID: PMC8472004 DOI: 10.3390/mi12091057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/24/2021] [Accepted: 08/26/2021] [Indexed: 12/29/2022]
Abstract
Hydrogels are the ideal materials in the development of implanted bioactive neural interfaces because of the nerve tissue-mimicked physical and biological properties that can enhance neural interfacing compatibility. However, the integration of hydrogels and rigid/dehydrated electronic microstructure is challenging due to the non-reliable interfacial bonding, whereas hydrogels are not compatible with most conditions required for the micromachined fabrication process. Herein, we propose a new enzyme-mediated transfer printing process to design an adhesive biological hydrogel neural interface. The donor substrate was fabricated via photo-crosslinking of gelatin methacryloyl (GelMA) containing various conductive nanoparticles (NPs), including Ag nanowires (NWs), Pt NWs, and PEDOT:PSS, to form a stretchable conductive bioelectrode, called NP-doped GelMA. On the other hand, a receiver substrate composed of microbial transglutaminase-incorporated gelatin (mTG-Gln) enabled simultaneous temporally controlled gelation and covalent bond-enhanced adhesion to achieve one-step transfer printing of the prefabricated NP-doped GelMA features. The integrated hydrogel microelectrode arrays (MEA) were adhesive, and mechanically/structurally bio-compliant with stable conductivity. The devices were structurally stable in moisture to support the growth of neuronal cells. Despite that the introduction of AgNW and PEDOT:PSS NPs in the hydrogels needed further study to avoid cell toxicity, the PtNW-doped GelMA exhibited a comparable live cell density. This Gln-based MEA is expected to be the next-generation bioactive neural interface.
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33
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Hierarchical platinum–iridium neural electrodes structured by femtosecond laser for superwicking interface and superior charge storage capacity. Biodes Manuf 2021. [DOI: 10.1007/s42242-021-00160-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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34
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Woo H, Kim S, Nam H, Choi W, Shin K, Kim K, Yoon S, Kim GH, Kim J, Lim G. Au Hierarchical Nanostructure-Based Surface Modification of Microelectrodes for Improved Neural Signal Recording. Anal Chem 2021; 93:11765-11774. [PMID: 34387479 DOI: 10.1021/acs.analchem.1c02168] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microelectrodes are widely used for neural signal analysis because they can record high-resolution signals. In general, the smaller the size of the microelectrode for obtaining a high-resolution signal, the higher the impedance and noise value of the electrodes. Therefore, to improve the signal-to-noise ratio (SNR) of neural signals, it is important to develop microelectrodes with low impedance and noise. In this research, an Au hierarchical nanostructure (AHN) was deposited to improve the electrochemical surface area (ECSA) of a microelectrode. Au nanostructures on different scales were deposited on the electrode surface in a hierarchical structure using an electrochemical deposition method. The AHN-modified microelectrode exhibited an average of 80% improvement in impedance compared to a bare microelectrode. Through electrochemical impedance spectroscopy analysis and impedance equivalent circuit modeling, the increase in the ECSA due to the AHN was confirmed. After evaluating the cell cytotoxicity of the AHN-modified microelectrode through an in vitro test, neural signals from rats were obtained in in vivo experiments. The AHN-modified microelectrode exhibited an approximate 9.79 dB improvement in SNR compared to the bare microelectrode. This surface modification technology is a post-treatment strategy used for existing fabricated electrodes, so it can be applied to microelectrode arrays and nerve electrodes made from various structures and materials.
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Affiliation(s)
| | | | | | - Wonsuk Choi
- Center for Bionics, Korea Institute of Science and Technology (KIST), 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Kumjae Shin
- Construction Equipment Technology Center, Korea Institute of Industrial Technology (KITECH), 288-1, Daehak-ri, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 38408, Republic of Korea
| | | | | | - Geon Hwee Kim
- School of Mechanical Engineering, Chungbuk National University (CBNU), 1, Chungdae-ro, Seowon-gu, Cheongju-si, Chungcheongbuk-do 28644, Republic of Korea
| | - Jinseok Kim
- Center for Bionics, Korea Institute of Science and Technology (KIST), 5, Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea
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35
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Rocha I, Cerqueira G, Varella Penteado F, Córdoba de Torresi SI. Electrical Stimulation and Conductive Polymers as a Powerful Toolbox for Tailoring Cell Behaviour in vitro. FRONTIERS IN MEDICAL TECHNOLOGY 2021; 3:670274. [PMID: 35047926 PMCID: PMC8757900 DOI: 10.3389/fmedt.2021.670274] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 06/17/2021] [Indexed: 12/26/2022] Open
Abstract
Electrical stimulation (ES) is a well-known method for guiding the behaviour of nerve cells in in vitro systems based on the response of these cells to an electric field. From this perspective, understanding how the electrochemical stimulus can be tuned for the design of a desired cell response is of great importance. Most biomedical studies propose the application of an electrical potential to cell culture arrays while examining the cell response regarding viability, morphology, and gene expression. Conversely, various studies failed to evaluate how the fine physicochemical properties of the materials used for cell culture influence the observed behaviours. Among the various materials used for culturing cells under ES, conductive polymers (CPs) are widely used either in pristine form or in addition to other polymers. CPs themselves do not possess the optimal surface for cell compatibility because of their hydrophobic nature, which leads to poor protein adhesion and, hence, poor bioactivity. Therefore, understanding how to tailor the chemical properties on the material surface will determine the obtention of improved ES platforms. Moreover, the structure of the material, either in a thin film or in porous electrospun scaffolds, also affects the biochemical response and needs to be considered. In this review, we examine how materials based on CPs influence cell behaviour under ES, and we compile the various ES setups and physicochemical properties that affect cell behaviour. This review concerns the culture of various cell types, such as neurons, fibroblasts, osteoblasts, and Schwann cells, and it also covers studies on stem cells prone to ES. To understand the mechanistic behaviour of these devices, we also examine studies presenting a more detailed biomolecular level of interaction. This review aims to guide the design of future ES setups regarding the influence of material properties and electrochemical conditions on the behaviour of in vitro cell studies.
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Affiliation(s)
- Igor Rocha
- Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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36
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Sunwoo SH, Ha KH, Lee S, Lu N, Kim DH. Wearable and Implantable Soft Bioelectronics: Device Designs and Material Strategies. Annu Rev Chem Biomol Eng 2021; 12:359-391. [PMID: 34097846 DOI: 10.1146/annurev-chembioeng-101420-024336] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
High-performance wearable and implantable devices capable of recording physiological signals and delivering appropriate therapeutics in real time are playing a pivotal role in revolutionizing personalized healthcare. However, the mechanical and biochemical mismatches between rigid, inorganic devices and soft, organic human tissues cause significant trouble, including skin irritation, tissue damage, compromised signal-to-noise ratios, and limited service time. As a result, profuse research efforts have been devoted to overcoming these issues by using flexible and stretchable device designs and soft materials. Here, we summarize recent representative research and technological advances for soft bioelectronics, including conformable and stretchable device designs, various types of soft electronic materials, and surface coating and treatment methods. We also highlight applications of these strategies to emerging soft wearable and implantable devices. We conclude with some current limitations and offer future prospects of this booming field.
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Affiliation(s)
- Sung-Hyuk Sunwoo
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea; .,School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Kyoung-Ho Ha
- Department of Mechanical Engineering, The University of Texas at Austin, Texas 78712, USA;
| | - Sangkyu Lee
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea;
| | - Nanshu Lu
- Department of Mechanical Engineering, The University of Texas at Austin, Texas 78712, USA; .,Center for Mechanics of Solids, Structures and Materials, Department of Aerospace Engineering and Engineering Mechanics, Department of Biomedical Engineering, and Texas Material Institute, The University of Texas at Austin, Texas 78712, USA
| | - Dae-Hyeong Kim
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea; .,School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea.,Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea
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37
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Gori M, Vadalà G, Giannitelli SM, Denaro V, Di Pino G. Biomedical and Tissue Engineering Strategies to Control Foreign Body Reaction to Invasive Neural Electrodes. Front Bioeng Biotechnol 2021; 9:659033. [PMID: 34113605 PMCID: PMC8185207 DOI: 10.3389/fbioe.2021.659033] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/27/2021] [Indexed: 12/21/2022] Open
Abstract
Neural-interfaced prostheses aim to restore sensorimotor limb functions in amputees. They rely on bidirectional neural interfaces, which represent the communication bridge between nervous system and neuroprosthetic device by controlling its movements and evoking sensory feedback. Compared to extraneural electrodes (i.e., epineural and perineural implants), intraneural electrodes, implanted within peripheral nerves, have higher selectivity and specificity of neural signal recording and nerve stimulation. However, being implanted in the nerve, their main limitation is represented by the significant inflammatory response that the body mounts around the probe, known as Foreign Body Reaction (FBR), which may hinder their rapid clinical translation. Furthermore, the mechanical mismatch between the consistency of the device and the surrounding neural tissue may contribute to exacerbate the inflammatory state. The FBR is a non-specific reaction of the host immune system to a foreign material. It is characterized by an early inflammatory phase eventually leading to the formation of a fibrotic capsule around intraneural interfaces, which increases the electrical impedance over time and reduces the chronic interface biocompatibility and functionality. Thus, the future in the reduction and control of the FBR relies on innovative biomedical strategies for the fabrication of next-generation neural interfaces, such as the development of more suitable designs of the device with smaller size, appropriate stiffness and novel conductive and biomimetic coatings for improving their long-term stability and performance. Here, we present and critically discuss the latest biomedical approaches from material chemistry and tissue engineering for controlling and mitigating the FBR in chronic neural implants.
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Affiliation(s)
- Manuele Gori
- Laboratory for Regenerative Orthopaedics, Department of Orthopaedic Surgery and Traumatology, Università Campus Bio-Medico di Roma, Rome, Italy
- Institute of Biochemistry and Cell Biology (IBBC) - National Research Council (CNR), Rome, Italy
| | - Gianluca Vadalà
- Laboratory for Regenerative Orthopaedics, Department of Orthopaedic Surgery and Traumatology, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Sara Maria Giannitelli
- Laboratory of Tissue Engineering, Department of Engineering, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Vincenzo Denaro
- Laboratory for Regenerative Orthopaedics, Department of Orthopaedic Surgery and Traumatology, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Giovanni Di Pino
- NeXT: Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit, Università Campus Bio-Medico di Roma, Rome, Italy
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38
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Jeon J, Yoon SH, Oh MA, Cho W, Kim JY, Shin CI, Kim EJ, Chung TD. Neuroligin-1-Modified Electrodes for Specific Coupling with a Presynaptic Neuronal Membrane. ACS APPLIED MATERIALS & INTERFACES 2021; 13:21944-21953. [PMID: 33909393 DOI: 10.1021/acsami.1c01298] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Coordination of synapses onto electrodes with high specificity and maintaining a stable and long-lasting interface have importance in the field of neural interfaces. One potential approach is to present ligands on the surface of electrodes that would be bound through a protein-protein interaction to specific areas of neuronal cells. Here, we functionalize electrode surfaces with genetically engineered neuroligin-1 protein and demonstrate the formation of a nascent presynaptic bouton upon binding to neurexin-1 β on the presynaptic membrane of neurons. The resulting synaptically connected electrode shows an assembly of presynaptic proteins and comparable exocytosis kinetics to that of native synapses. Importantly, a neuroligin-1-induced synapse-electrode interface exhibits type specificity and structural robustness. We envision that the use of synaptic adhesion proteins in modified neural electrodes may lead to new approaches in the interfacing of neural circuity and electronics.
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Affiliation(s)
- Joohee Jeon
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Sun-Heui Yoon
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Min-Ah Oh
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Wonkyung Cho
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Ji Yong Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Chang Il Shin
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Eun Joong Kim
- Advanced Institute of Convergence Technology, Suwon-Si 16229, Gyeonggi-do, Republic of Korea
| | - Taek Dong Chung
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
- Advanced Institute of Convergence Technology, Suwon-Si 16229, Gyeonggi-do, Republic of Korea
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McGlynn E, Nabaei V, Ren E, Galeote‐Checa G, Das R, Curia G, Heidari H. The Future of Neuroscience: Flexible and Wireless Implantable Neural Electronics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002693. [PMID: 34026431 PMCID: PMC8132070 DOI: 10.1002/advs.202002693] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/15/2021] [Indexed: 05/04/2023]
Abstract
Neurological diseases are a prevalent cause of global mortality and are of growing concern when considering an ageing global population. Traditional treatments are accompanied by serious side effects including repeated treatment sessions, invasive surgeries, or infections. For example, in the case of deep brain stimulation, large, stiff, and battery powered neural probes recruit thousands of neurons with each pulse, and can invoke a vigorous immune response. This paper presents challenges in engineering and neuroscience in developing miniaturized and biointegrated alternatives, in the form of microelectrode probes. Progress in design and topology of neural implants has shifted the goal post toward highly specific recording and stimulation, targeting small groups of neurons and reducing the foreign body response with biomimetic design principles. Implantable device design recommendations, fabrication techniques, and clinical evaluation of the impact flexible, integrated probes will have on the treatment of neurological disorders are provided in this report. The choice of biocompatible material dictates fabrication techniques as novel methods reduce the complexity of manufacture. Wireless power, the final hurdle to truly implantable neural interfaces, is discussed. These aspects are the driving force behind continued research: significant breakthroughs in any one of these areas will revolutionize the treatment of neurological disorders.
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Affiliation(s)
- Eve McGlynn
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Vahid Nabaei
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Elisa Ren
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Gabriel Galeote‐Checa
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Rupam Das
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Giulia Curia
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Hadi Heidari
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
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Czerwińska-Główka D, Przystaś W, Zabłocka-Godlewska E, Student S, Cwalina B, Łapkowski M, Krukiewicz K. Electrically-responsive antimicrobial coatings based on a tetracycline-loaded poly(3,4-ethylenedioxythiophene) matrix. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 123:112017. [PMID: 33812635 DOI: 10.1016/j.msec.2021.112017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 02/09/2021] [Accepted: 03/02/2021] [Indexed: 11/17/2022]
Abstract
The growth of bacteria and the formation of complex bacterial structures on biomedical devices is a major challenge in modern medicine. The aim of this study was to develop a biocompatible, conducting and antibacterial polymer coating applicable in biomedical engineering. Since conjugated polymers have recently aroused strong interest as controlled delivery systems for biologically active compounds, we decided to employ a poly(3,4-ethylenedioxythiophene) (PEDOT) matrix to immobilize a powerful, first-line antibiotic: tetracycline (Tc). Drug immobilization was carried out simultaneously with the electrochemical polymerization process, allowing to obtain a polymer coating with good electrochemical behaviour (charge storage capacity of 19.15 ± 6.09 mC/cm2) and high drug loading capacity (194.7 ± 56.2 μg/cm2). Biological activity of PEDOT/Tc matrix was compared with PEDOT matrix and a bare Pt surface against a model Gram-negative bacteria strain of Escherichia coli with the use of LIVE/DEAD assay and SEM microscopy. Finally, PEDOT/Tc was shown to serve as a robust electroactive coating exhibiting antibacterial activity.
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Affiliation(s)
- Dominika Czerwińska-Główka
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Gliwice, Poland
| | - Wioletta Przystaś
- Department of Environmental Biotechnology, Faculty of Energy and Environmental Engineering, Silesian University of Technology, Gliwice, Poland; Biotechnology Centre, Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland
| | - Ewa Zabłocka-Godlewska
- Department of Environmental Biotechnology, Faculty of Energy and Environmental Engineering, Silesian University of Technology, Gliwice, Poland; Biotechnology Centre, Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland
| | - Sebastian Student
- Biotechnology Centre, Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland; Department of Systems Biology and Engineering, Faculty of Automatic Control, Electronics and Computer Science, Silesian University of Technology, Gliwice, Poland
| | - Beata Cwalina
- Department of Environmental Biotechnology, Faculty of Energy and Environmental Engineering, Silesian University of Technology, Gliwice, Poland; Biotechnology Centre, Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland
| | - Mieczysław Łapkowski
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Gliwice, Poland; Centre of Polymer and Carbon Materials, Polish Academy of Sciences, M. Curie-Sklodowskiej 34, Zabrze, Poland
| | - Katarzyna Krukiewicz
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Gliwice, Poland.
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Abstract
Peripheral nerve interfaces (PNIs) record and/or modulate neural activity of nerves, which are responsible for conducting sensory-motor information to and from the central nervous system, and for regulating the activity of inner organs. PNIs are used both in neuroscience research and in therapeutical applications such as precise closed-loop control of neuroprosthetic limbs, treatment of neuropathic pain and restoration of vital functions (e.g. breathing and bladder management). Implantable interfaces represent an attractive solution to directly access peripheral nerves and provide enhanced selectivity both in recording and in stimulation, compared to their non-invasive counterparts. Nevertheless, the long-term functionality of implantable PNIs is limited by tissue damage, which occurs at the implant-tissue interface, and is thus highly dependent on material properties, biocompatibility and implant design. Current research focuses on the development of mechanically compliant PNIs, which adapt to the anatomy and dynamic movements of nerves in the body thereby limiting foreign body response. In this paper, we review recent progress in the development of flexible and implantable PNIs, highlighting promising solutions related to materials selection and their associated fabrication methods, and integrated functions. We report on the variety of available interface designs (intraneural, extraneural and regenerative) and different modulation techniques (electrical, optical, chemical) emphasizing the main challenges associated with integrating such systems on compliant substrates.
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Affiliation(s)
- Valentina Paggi
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland. Equally contributing authors
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Cai L, Gutruf P. Soft, Wireless and subdermally implantable recording and neuromodulation tools. J Neural Eng 2021; 18. [PMID: 33607646 DOI: 10.1088/1741-2552/abe805] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 02/19/2021] [Indexed: 12/14/2022]
Abstract
Progress in understanding neuronal interaction and circuit behavior of the central and peripheral nervous system strongly relies on the advancement of tools that record and stimulate with high fidelity and specificity. Currently, devices used in exploratory research predominantly utilize cables or tethers to provide pathways for power supply, data communication, stimulus delivery and recording, which constrains the scope and use of such devices. In particular, the tethered connection, mechanical mismatch to surrounding soft tissues and bones frustrate the interface leading to irritation and limitation of motion of the subject, which in the case of fundamental and preclinical studies, impacts naturalistic behaviors of animals and precludes the use in experiments involving social interaction and ethologically relevant three-dimensional environments, limiting the use of current tools to mostly rodents and exclude species such as birds and fish. This review explores the current state-of-the-art in wireless, subdermally implantable tools that quantitively expand capabilities in analysis and perturbation of the central and peripheral nervous system by removing tethers and externalized features of implantable neuromodulation and recording tools. Specifically, the review explores power harvesting strategies, wireless communication schemes, and soft materials and mechanics that enable the creation of such devices and discuss their capabilities in the context of freely-behaving subjects. Highlights of this class of devices includes wireless battery-free and fully implantable operation with capabilities in cell specific recording, multimodal neural stimulation and electrical, optogenetic and pharmacological neuromodulation capabilities. We conclude with discussion on translation of such technologies which promises routes towards broad dissemination.
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Affiliation(s)
- Le Cai
- Biomedical Engineering, University of Arizona, 1230 N Cherry Ave., Tucson, Arizona, 85719, UNITED STATES
| | - Philipp Gutruf
- Biomedical Engineering, University of Arizona, 1230 N Cherry Ave., Tucson, Arizona, 85719, UNITED STATES
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43
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Rihani R, Tasnim N, Javed M, Usoro JO, D'Souza TM, Ware TH, Pancrazio JJ. Liquid Crystalline Polymers: Opportunities to Shape Neural Interfaces. Neuromodulation 2021; 25:1259-1267. [PMID: 33501705 DOI: 10.1111/ner.13364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/21/2020] [Accepted: 01/05/2021] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Polymers have emerged as constituent materials for the creation of microscale neural interfaces; however, limitations regarding water permeability, delamination, and material degradation impact polymeric device robustness. Liquid crystal polymers (LCPs) have molecular order like a solid but with the fluidity of a liquid, resulting in a unique material, with properties including low water permeability, chemical inertness, and mechanical toughness. The objective of this article is to review the state-of-the-art regarding the use of LCPs in neural interface applications and discuss challenges and opportunities where this class of materials can advance the field of neural interfaces. MATERIALS AND METHODS This review article focuses on studies that leverage LCP materials to interface with the nervous system in vivo. A comprehensive literature search was performed using PubMed, Web of Science (Clarivate Analytics), and Google Scholar. RESULTS There have been recent efforts to create neural interfaces that leverage the material advantages of LCPs. The literature offers examples of LCP as a basis for implantable medical devices and neural interfaces in the form of planar electrode arrays for retinal prosthetic, electrocorticography applications, and cuff-like structures for interfacing the peripheral nerve. In addition, there have been efforts to create penetrating intracortical devices capable of microstimulation and resolution of biopotentials. Recent work with a subclass of LCPs, namely liquid crystal elastomers, demonstrates that it is possible to create devices with features that deploy away from a central implantation site to interface with a volume of tissue while offering the possibility of minimizing tissue damage. CONCLUSION We envision the creation of novel microscale neural interfaces that leverage the physical properties of LCPs and have the capability of deploying within neural tissue for enhanced integration and performance.
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Affiliation(s)
- Rashed Rihani
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Nishat Tasnim
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Mahjabeen Javed
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.,Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Joshua O Usoro
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Tania M D'Souza
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Taylor H Ware
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.,Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA.,Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
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Forro C, Caron D, Angotzi GN, Gallo V, Berdondini L, Santoro F, Palazzolo G, Panuccio G. Electrophysiology Read-Out Tools for Brain-on-Chip Biotechnology. MICROMACHINES 2021; 12:124. [PMID: 33498905 PMCID: PMC7912435 DOI: 10.3390/mi12020124] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 02/07/2023]
Abstract
Brain-on-Chip (BoC) biotechnology is emerging as a promising tool for biomedical and pharmaceutical research applied to the neurosciences. At the convergence between lab-on-chip and cell biology, BoC couples in vitro three-dimensional brain-like systems to an engineered microfluidics platform designed to provide an in vivo-like extrinsic microenvironment with the aim of replicating tissue- or organ-level physiological functions. BoC therefore offers the advantage of an in vitro reproduction of brain structures that is more faithful to the native correlate than what is obtained with conventional cell culture techniques. As brain function ultimately results in the generation of electrical signals, electrophysiology techniques are paramount for studying brain activity in health and disease. However, as BoC is still in its infancy, the availability of combined BoC-electrophysiology platforms is still limited. Here, we summarize the available biological substrates for BoC, starting with a historical perspective. We then describe the available tools enabling BoC electrophysiology studies, detailing their fabrication process and technical features, along with their advantages and limitations. We discuss the current and future applications of BoC electrophysiology, also expanding to complementary approaches. We conclude with an evaluation of the potential translational applications and prospective technology developments.
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Affiliation(s)
- Csaba Forro
- Tissue Electronics, Fondazione Istituto Italiano di Tecnologia, Largo Barsanti e Matteucci, 53-80125 Naples, Italy; (C.F.); (F.S.)
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Davide Caron
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| | - Gian Nicola Angotzi
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (G.N.A.); (L.B.)
| | - Vincenzo Gallo
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| | - Luca Berdondini
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (G.N.A.); (L.B.)
| | - Francesca Santoro
- Tissue Electronics, Fondazione Istituto Italiano di Tecnologia, Largo Barsanti e Matteucci, 53-80125 Naples, Italy; (C.F.); (F.S.)
| | - Gemma Palazzolo
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| | - Gabriella Panuccio
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
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Wang C, Yokota T, Someya T. Natural Biopolymer-Based Biocompatible Conductors for Stretchable Bioelectronics. Chem Rev 2021; 121:2109-2146. [DOI: 10.1021/acs.chemrev.0c00897] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Chunya Wang
- Department of Electrical Engineering and Information Systems, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Tomoyuki Yokota
- Department of Electrical Engineering and Information Systems, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Takao Someya
- Department of Electrical Engineering and Information Systems, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Thin-Film Device Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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46
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Chen K, Wellman SM, Yaxiaer Y, Eles JR, Kozai TD. In vivo spatiotemporal patterns of oligodendrocyte and myelin damage at the neural electrode interface. Biomaterials 2020; 268:120526. [PMID: 33302121 DOI: 10.1016/j.biomaterials.2020.120526] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/26/2022]
Abstract
Intracortical microelectrodes with the ability to detect intrinsic electrical signals and/or deliver electrical stimulation into local brain regions have been a powerful tool to understand brain circuitry and for therapeutic applications to neurological disorders. However, the chronic stability and sensitivity of these intracortical microelectrodes are challenged by overwhelming biological responses, including severe neuronal loss and thick glial encapsulation. Unlike microglia and astrocytes whose activity have been extensively examined, oligodendrocytes and their myelin processes remain poorly studied within the neural interface field. Oligodendrocytes have been widely recognized to modulate electrical signal conductance along axons through insulating myelin segments. Emerging evidence offers an alternative perspective on neuron-oligodendrocyte coupling where oligodendrocytes provide metabolic and neurotrophic support to neurons through cytoplasmic myelin channels and monocarboxylate transporters. This study uses in vivo multi-photon microscopy to gain insights into the dynamics of oligodendrocyte soma and myelin processes in response to chronic device implantation injury over 4 weeks. We observe that implantation induces acute oligodendrocyte injury including initial deformation and substantial myelinosome formation, an early sign of myelin injury. Over chronic implantation periods, myelin and oligodendrocyte soma suffer severe degeneration proximal to the interface. Interestingly, wound healing attempts such as oligodendrogenesis are initiated over time, however they are hampered by continued degeneration near the implant. Nevertheless, this detailed characterization of oligodendrocyte spatiotemporal dynamics during microelectrode-induced inflammation may provide insights for novel intervention targets to facilitate oligodendrogenesis, enhance the integration of neural-electrode interfaces, and improve long-term functional performance.
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Affiliation(s)
- Keying Chen
- Department of Bioengineering, University of Pittsburgh, USA; Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, USA
| | - Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, USA; Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, USA
| | - Yalikun Yaxiaer
- Eberly College of Science, Pennsylvania State University, University Park, USA
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, USA; Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, USA
| | - Takashi Dy Kozai
- Department of Bioengineering, University of Pittsburgh, USA; Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, USA; Center for Neuroscience, University of Pittsburgh, USA; McGowan Institute of Regenerative Medicine, University of Pittsburgh, USA; NeuroTech Center, University of Pittsburgh Brain Institute, USA.
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Vallejo-Giraldo C, Genta M, Cauvi O, Goding J, Green R. Hydrogels for 3D Neural Tissue Models: Understanding Cell-Material Interactions at a Molecular Level. Front Bioeng Biotechnol 2020; 8:601704. [PMID: 33240868 PMCID: PMC7677185 DOI: 10.3389/fbioe.2020.601704] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/14/2020] [Indexed: 11/13/2022] Open
Abstract
The development of 3D neural tissue analogs is of great interest to a range of biomedical engineering applications including tissue engineering of neural interfaces, treatment of neurodegenerative diseases and in vitro assessment of cell-material interactions. Despite continued efforts to develop synthetic or biosynthetic hydrogels which promote the development of complex neural networks in 3D, successful long-term 3D approaches have been restricted to the use of biologically derived constructs. In this study a poly (vinyl alcohol) biosynthetic hydrogel functionalized with gelatin and sericin (PVA-SG), was used to understand the interplay between cell-cell communication and cell-material interaction. This was used to probe critical short-term interactions that determine the success or failure of neural network growth and ultimately the development of a useful model. Complex primary ventral mesencephalic (VM) neural cells were encapsulated in PVA-SG hydrogels and critical molecular cues that demonstrate mechanosensory interaction were examined. Neuronal presence was constant over the 10 day culture, but the astrocyte population decreased in number. The lack of astrocytic support led to a reduction in neural process outgrowth from 24.0 ± 1.3 μm on Day 7 to 7.0 ± 0.1 μm on Day 10. Subsequently, purified astrocytes were studied in isolation to understand the reasons behind PVA-SG hydrogel inability to support neural network development. It was proposed that the spatially restrictive nature (or tight mesh size) of PVA-SG hydrogels limited the astrocytic actin polymerization together with a cytoplasmic-nuclear translocation of YAP over time, causing an alteration in their cell cycle. This was confirmed by the evaluation of p27/Kip1 gene that was found to be upregulated by a twofold increase in expression at both Days 7 and 10 compared to Day 3, indicating the quiescent stage of the astrocytes in PVA-SG hydrogel. Cell migration was further studied by the quantification of MMP-2 production that was negligible compared to 2D controls, ranging from 2.7 ± 2.3% on Day 3 to 5.3 ± 2.9% on Day 10. This study demonstrates the importance of understanding astrocyte-material interactions at the molecular level, with the need to address spatial constraints in the 3D hydrogel environment. These findings will inform the design of future hydrogel constructs with greater capacity for remodeling by the cell population to create space for cell migration and neural process extension.
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Affiliation(s)
| | - Martina Genta
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Olivia Cauvi
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Josef Goding
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Rylie Green
- Department of Bioengineering, Imperial College London, London, United Kingdom
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Ritzau-Reid KI, Spicer CD, Gelmi A, Grigsby CL, Ponder JF, Bemmer V, Creamer A, Vilar R, Serio A, Stevens MM. An Electroactive Oligo-EDOT Platform for Neural Tissue Engineering. ADVANCED FUNCTIONAL MATERIALS 2020; 30:2003710. [PMID: 34035794 PMCID: PMC7610826 DOI: 10.1002/adfm.202003710] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Indexed: 05/04/2023]
Abstract
The unique electrochemical properties of the conductive polymer poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) make it an attractive material for use in neural tissue engineering applications. However, inadequate mechanical properties, and difficulties in processing and lack of biodegradability have hindered progress in this field. Here, the functionality of PEDOT:PSS for neural tissue engineering is improved by incorporating 3,4-ethylenedioxythiophene (EDOT) oligomers, synthesized using a novel end-capping strategy, into block co-polymers. By exploiting end-functionalized oligoEDOT constructs as macroinitiators for the polymerization of poly(caprolactone), a block co-polymer is produced that is electroactive, processable, and bio-compatible. By combining these properties, electroactive fibrous mats are produced for neuronal culture via solution electrospinning and melt electrospinning writing. Importantly, it is also shown that neurite length and branching of neural stem cells can be enhanced on the materials under electrical stimulation, demonstrating the promise of these scaffolds for neural tissue engineering.
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Affiliation(s)
- Kaja I. Ritzau-Reid
- Department of Materials, Department of Bioengineering, Institute of
Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Christopher D. Spicer
- Department of Materials, Department of Bioengineering, Institute of
Biomedical Engineering, Imperial College London, London SW7 2AZ, UK;
Department of Medical Biochemistry and Biophysics, Karolinska Institutet,
Stockholm 171 77, Sweden; Department of Chemistry, York Biomedical Research
Institute, University of York, Heslington YO10 5DD, UK
| | - Amy Gelmi
- Department of Materials, Department of Bioengineering, Institute of
Biomedical Engineering, Imperial College London, London SW7 2AZ, UK; Applied
Chemistry and Environmental Science, School of Science, RMIT University,
Melbourne 3000, Australia
| | - Christopher L. Grigsby
- Department of Medical Biochemistry and Biophysics, Karolinska
Institutet, Stockholm 171 77, Sweden
| | - James F. Ponder
- Department of Chemistry, Imperial College London, London SW7 2AZ,
UK
| | - Victoria Bemmer
- Department of Materials, Department of Bioengineering, Institute of
Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Adam Creamer
- Department of Materials, Department of Bioengineering, Institute of
Biomedical Engineering, Imperial College London, London SW7 2AZ, UK
| | - Ramon Vilar
- Department of Chemistry, Imperial College London, London SW7 2AZ,
UK
| | - Andrea Serio
- Department of Materials, Department of Bioengineering, Institute of
Biomedical Engineering, Imperial College London, London SW7 2AZ, UK; Centre
for Craniofacial & Regenerative Biology, King’s College London
and The Francis Crick Institute, Tissue Engineering and Biophotonics
Division, Dental Institute, King’s College London, London SE1 9RT,
UK
| | - Molly M. Stevens
- Department of Materials, Department of Bioengineering, Institute
of Biomedical Engineering, Imperial College London, London SW7 2AZ, UK;
Department of Medical Biochemistry and Biophysics, Karolinska Institutet,
Stockholm 171 77, Sweden
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Sikder MKU, Tong W, Pingle H, Kingshott P, Needham K, Shivdasani MN, Fallon JB, Seligman P, Ibbotson MR, Prawer S, Garrett DJ. Laminin coated diamond electrodes for neural stimulation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 118:111454. [PMID: 33255039 DOI: 10.1016/j.msec.2020.111454] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 07/15/2020] [Accepted: 08/25/2020] [Indexed: 12/20/2022]
Abstract
The performance of many implantable neural stimulation devices is degraded due to the loss of neurons around the electrodes by the body's natural biological responses to a foreign material. Coating of electrodes with biomolecules such as extracellular matrix proteins is one potential route to suppress the adverse responses that lead to loss of implant functionality. Concurrently, however, the electrochemical performance of the stimulating electrode must remain optimal to continue to safely provide sufficient charge for neural stimulation. We have previously found that oxygen plasma treated nitrogen included ultrananocrystalline diamond coated platinum electrodes exhibit superior charge injection capacity and electrochemical stability for neural stimulation (Sikder et al., 2019). To fabricate bioactive diamond electrodes, in this work, laminin, an extracellular matrix protein known to be involved in inter-neuron adhesion and recognition, was used as an example biomolecule. Here, laminin was covalently coupled to diamond electrodes. Electrochemical analysis found that the covalently coupled films were robust and resulted in minimal change to the charge injection capacity of diamond electrodes. The successful binding of laminin and its biological activity was further confirmed using primary rat cortical neuron cultures, and the coated electrodes showed enhanced cell attachment densities and neurite outgrowth. The method proposed in this work is versatile and adaptable to many other biomolecules for producing bioactive diamond electrodes, which are expected to show reduced the inflammatory responses in vivo.
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Affiliation(s)
- Md Kabir Uddin Sikder
- Department of Medical Bionics, The University of Melbourne, Parkville, Melbourne, VIC 3010, Australia; Bionics Institute, 384 Albert St, East Melbourne, VIC 3002, Australia; Department of Physics, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh
| | - Wei Tong
- National Vision Research Institute, Australian College of Optometry, Carlton, VIC 3010, Australia; School of Physics, The University of Melbourne, Parkville, Melbourne, VIC 3010, Australia; Department of Optometry and Vision Sciences, Melbourne School of Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia.
| | - Hitesh Pingle
- ARC Training Centre Training Centre in Surface Engineering for Advanced Materials (SEAM), Department of Chemistry and Biotechnology, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Peter Kingshott
- ARC Training Centre Training Centre in Surface Engineering for Advanced Materials (SEAM), Department of Chemistry and Biotechnology, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Karina Needham
- Department of Otolaryngology, The University of Melbourne, Royal Victorian Eye & Ear Hospital, East Melbourne, Australia
| | - Mohit N Shivdasani
- Bionics Institute, 384 Albert St, East Melbourne, VIC 3002, Australia; Graduate School of Biomedical Engineering, The University of New South Wales, Kensington, NSW 2033, Australia
| | - James B Fallon
- Department of Medical Bionics, The University of Melbourne, Parkville, Melbourne, VIC 3010, Australia; Bionics Institute, 384 Albert St, East Melbourne, VIC 3002, Australia; Department of Otolaryngology, The University of Melbourne, Royal Victorian Eye & Ear Hospital, East Melbourne, Australia
| | - Peter Seligman
- Bionics Institute, 384 Albert St, East Melbourne, VIC 3002, Australia
| | - Michael R Ibbotson
- National Vision Research Institute, Australian College of Optometry, Carlton, VIC 3010, Australia; Department of Optometry and Vision Sciences, Melbourne School of Health Sciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Steven Prawer
- School of Physics, The University of Melbourne, Parkville, Melbourne, VIC 3010, Australia
| | - David J Garrett
- School of Physics, The University of Melbourne, Parkville, Melbourne, VIC 3010, Australia; RMIT University, School of Engineering, Melbourne, VIC 3001, Australia
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Nikiforidis G, Wustoni S, Routier C, Hama A, Koklu A, Saleh A, Steiner N, Druet V, Fiumelli H, Inal S. Benchmarking the Performance of Electropolymerized Poly(3,4-ethylenedioxythiophene) Electrodes for Neural Interfacing. Macromol Biosci 2020; 20:e2000215. [PMID: 32820588 DOI: 10.1002/mabi.202000215] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/03/2020] [Indexed: 11/11/2022]
Abstract
The development of electronics adept at interfacing with the nervous system is an ever-growing effort, leading to discoveries in fundamental neuroscience applied in clinical setting. Highly capacitive and electrochemically stable electronic materials are paramount for these advances. A systematic study is presented where copolymers based on 3,4-ethylenedioxythiophene (EDOT) and its hydroxyl-terminated counterpart (EDOTOH) are electropolymerized in an aqueous solution in the presence of various counter anions and additives. Amongst the conducting materials developed, the copolymer p(EDOT-ran-EDOTOH) doped with perchlorate in the presence of ethylene glycol shows high specific capacitance (105 F g-1 ), and capacitance retention (85%) over 1000 galvanostatic charge-discharge cycles. A microelectrode array-based on this material is fabricated and primary cortical neurons are cultured therein for several days. The microelectrodes electrically stimulate targeted neuronal networks and record their activity with high signal-to-noise ratio. The stability of charge injection capacity of the material is validated via long-term pulsing experiments. While providing insights on the effect of additives and dopants on the electrochemical performance and operational stability of electropolymerized conducting polymers, this study highlights the importance of high capacitance accompanied with stability to achieve high performance electrodes for biological interfacing.
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Affiliation(s)
- Georgios Nikiforidis
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Shofarul Wustoni
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Cyril Routier
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Adel Hama
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Anil Koklu
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Abdulelah Saleh
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | | | - Victor Druet
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | | | - Sahika Inal
- Organic Bioelectronics Laboratory, Biological Science and Engineering Division (BESE), King Abdullah University of Science and Engineering (KAUST), Thuwal, 23955-6900, Saudi Arabia
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