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Ionescu ON, Franti E, Carbunaru V, Moldovan C, Dinulescu S, Ion M, Dragomir DC, Mihailescu CM, Lascar I, Oproiu AM, Neagu TP, Costea R, Dascalu M, Teleanu MD, Ionescu G, Teleanu R. System of Implantable Electrodes for Neural Signal Acquisition and Stimulation for Wirelessly Connected Forearm Prosthesis. BIOSENSORS 2024; 14:31. [PMID: 38248408 PMCID: PMC10813559 DOI: 10.3390/bios14010031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/31/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024]
Abstract
There is great interest in the development of prosthetic limbs capable of complex activities that are wirelessly connected to the patient's neural system. Although some progress has been achieved in this area, one of the main problems encountered is the selective acquisition of nerve impulses and the closing of the automation loop through the selective stimulation of the sensitive branches of the patient. Large-scale research and development have achieved so-called "cuff electrodes"; however, they present a big disadvantage: they are not selective. In this article, we present the progress made in the development of an implantable system of plug neural microelectrodes that relate to the biological nerve tissue and can be used for the selective acquisition of neuronal signals and for the stimulation of specific nerve fascicles. The developed plug electrodes are also advantageous due to their small thickness, as they do not trigger nerve inflammation. In addition, the results of the conducted tests on a sous scrofa subject are presented.
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Affiliation(s)
- Octavian Narcis Ionescu
- Faculty of Mechanical and Electrical Engineering, Petroleum and Gas University from Ploiesti, 100680 Ploiesti, Romania; (O.N.I.); (G.I.)
- National Institute for Research and Development for Microtechnology Bucharest, 077190 Bucharest, Romania; (C.M.); (S.D.); (M.I.); (D.C.D.); (C.M.M.)
| | - Eduard Franti
- National Institute for Research and Development for Microtechnology Bucharest, 077190 Bucharest, Romania; (C.M.); (S.D.); (M.I.); (D.C.D.); (C.M.M.)
- ICIA, Centre of New Electronic Architectures, 061071 Bucharest, Romania;
| | - Vlad Carbunaru
- Emergency Clinic Hospital Bucharest, 014461 Bucharest, Romania; (V.C.); (I.L.); (A.M.O.); (T.P.N.)
- University of Medicine and Pharmacy UMF Carol Davila, 050474 Bucharest, Romania; (M.D.T.); (R.T.)
| | - Carmen Moldovan
- National Institute for Research and Development for Microtechnology Bucharest, 077190 Bucharest, Romania; (C.M.); (S.D.); (M.I.); (D.C.D.); (C.M.M.)
| | - Silviu Dinulescu
- National Institute for Research and Development for Microtechnology Bucharest, 077190 Bucharest, Romania; (C.M.); (S.D.); (M.I.); (D.C.D.); (C.M.M.)
| | - Marian Ion
- National Institute for Research and Development for Microtechnology Bucharest, 077190 Bucharest, Romania; (C.M.); (S.D.); (M.I.); (D.C.D.); (C.M.M.)
| | - David Catalin Dragomir
- National Institute for Research and Development for Microtechnology Bucharest, 077190 Bucharest, Romania; (C.M.); (S.D.); (M.I.); (D.C.D.); (C.M.M.)
| | - Carmen Marinela Mihailescu
- National Institute for Research and Development for Microtechnology Bucharest, 077190 Bucharest, Romania; (C.M.); (S.D.); (M.I.); (D.C.D.); (C.M.M.)
| | - Ioan Lascar
- Emergency Clinic Hospital Bucharest, 014461 Bucharest, Romania; (V.C.); (I.L.); (A.M.O.); (T.P.N.)
- University of Medicine and Pharmacy UMF Carol Davila, 050474 Bucharest, Romania; (M.D.T.); (R.T.)
| | - Ana Maria Oproiu
- Emergency Clinic Hospital Bucharest, 014461 Bucharest, Romania; (V.C.); (I.L.); (A.M.O.); (T.P.N.)
- University of Medicine and Pharmacy UMF Carol Davila, 050474 Bucharest, Romania; (M.D.T.); (R.T.)
| | - Tiberiu Paul Neagu
- Emergency Clinic Hospital Bucharest, 014461 Bucharest, Romania; (V.C.); (I.L.); (A.M.O.); (T.P.N.)
- University of Medicine and Pharmacy UMF Carol Davila, 050474 Bucharest, Romania; (M.D.T.); (R.T.)
| | - Ruxandra Costea
- Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine of Bucharest, 011464 Bucharest, Romania;
| | - Monica Dascalu
- ICIA, Centre of New Electronic Architectures, 061071 Bucharest, Romania;
- Faculty of Electronics, Telecommunications and Information Technology, National University of Science and Technology Politehnica of Bucharest, 060042 Bucharest, Romania
| | - Mihai Daniel Teleanu
- University of Medicine and Pharmacy UMF Carol Davila, 050474 Bucharest, Romania; (M.D.T.); (R.T.)
| | - Gabriela Ionescu
- Faculty of Mechanical and Electrical Engineering, Petroleum and Gas University from Ploiesti, 100680 Ploiesti, Romania; (O.N.I.); (G.I.)
| | - Raluca Teleanu
- University of Medicine and Pharmacy UMF Carol Davila, 050474 Bucharest, Romania; (M.D.T.); (R.T.)
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McDonald M, Sebinger D, Brauns L, Gonzalez-Cano L, Menuchin-Lasowski Y, Mierzejewski M, Psathaki OE, Stumpf A, Wickham J, Rauen T, Schöler H, Jones PD. A mesh microelectrode array for non-invasive electrophysiology within neural organoids. Biosens Bioelectron 2023; 228:115223. [PMID: 36931193 DOI: 10.1016/j.bios.2023.115223] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/07/2023] [Accepted: 03/10/2023] [Indexed: 03/13/2023]
Abstract
Organoids are emerging in vitro models of human physiology. Neural models require the evaluation of functional activity of single cells and networks, which is commonly measured by microelectrode arrays. The characteristics of organoids clash with existing in vitro or in vivo microelectrode arrays. With inspiration from implantable mesh electronics and growth of organoids on polymer scaffolds, we fabricated suspended hammock-like mesh microelectrode arrays for neural organoids. We have demonstrated the growth of organoids enveloping these meshes and the culture of organoids on meshes for up to one year. Furthermore, we present proof-of-principle recordings of spontaneous electrical activity across the volume of an organoid. Our concept enables a new class of microelectrode arrays for in vitro models of three-dimensional electrically active tissue.
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Affiliation(s)
- Matthew McDonald
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, 72770, Reutlingen, Germany; Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany
| | - David Sebinger
- Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany
| | - Lisa Brauns
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, 72770, Reutlingen, Germany; Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany
| | - Laura Gonzalez-Cano
- Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany
| | | | - Michael Mierzejewski
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, 72770, Reutlingen, Germany; Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany
| | - Olympia-Ekaterini Psathaki
- Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany; University of Osnabrück, CellNanOs (Center of Cellular Nanoanalytics), Integrated Bioimaging Facility iBiOs, Barbarastr. 11, 49076, Osnabrück, Germany
| | - Angelika Stumpf
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, 72770, Reutlingen, Germany
| | - Jenny Wickham
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, 72770, Reutlingen, Germany
| | - Thomas Rauen
- Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany.
| | - Hans Schöler
- Max Planck Institute for Molecular Biomedicine, Röntgenstr. 20, 48149, Münster, Germany
| | - Peter D Jones
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, 72770, Reutlingen, Germany.
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Cehajic-Kapetanovic J, Singh MS, Zrenner E, MacLaren RE. Bioengineering strategies for restoring vision. Nat Biomed Eng 2023; 7:387-404. [PMID: 35102278 DOI: 10.1038/s41551-021-00836-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 11/30/2021] [Indexed: 12/15/2022]
Abstract
Late-stage retinal degenerative disease involving photoreceptor loss can be treated by optogenetic therapy, cell transplantation and retinal prostheses. These approaches aim to restore light sensitivity to the retina as well as visual perception by integrating neuronal responses for transmission to the cortex. In age-related macular degeneration, some cell-based therapies also aim to restore photoreceptor-supporting tissue to prevent complete photoreceptor loss. In the earlier stages of degeneration, gene-replacement therapy could attenuate retinal-disease progression and reverse loss of function. And gene-editing strategies aim to correct the underlying genetic defects. In this Review, we highlight the most promising gene therapies, cell therapies and retinal prostheses for the treatment of retinal disease, discuss the benefits and drawbacks of each treatment strategy and the factors influencing whether functional tissue is reconstructed and repaired or replaced with an electronic device, and summarize upcoming technologies for enhancing the restoration of vision.
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Affiliation(s)
- Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
| | | | - Eberhart Zrenner
- Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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Ahnood A, Chambers A, Gelmi A, Yong KT, Kavehei O. Semiconducting electrodes for neural interfacing: a review. Chem Soc Rev 2023; 52:1491-1518. [PMID: 36734845 DOI: 10.1039/d2cs00830k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In the past 50 years, the advent of electronic technology to directly interface with neural tissue has transformed the fields of medicine and biology. Devices that restore or even replace impaired bodily functions, such as deep brain stimulators and cochlear implants, have ushered in a new treatment era for previously intractable conditions. Meanwhile, electrodes for recording and stimulating neural activity have allowed researchers to unravel the vast complexities of the human nervous system. Recent advances in semiconducting materials have allowed effective interfaces between electrodes and neuronal tissue through novel devices and structures. Often these are unattainable using conventional metallic electrodes. These have translated into advances in research and treatment. The development of semiconducting materials opens new avenues in neural interfacing. This review considers this emerging class of electrodes and how it can facilitate electrical, optical, and chemical sensing and modulation with high spatial and temporal precision. Semiconducting electrodes have advanced electrically based neural interfacing technologies owing to their unique electrochemical and photo-electrochemical attributes. Key operation modalities, namely sensing and stimulation in electrical, biochemical, and optical domains, are discussed, highlighting their contrast to metallic electrodes from the application and characterization perspective.
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Affiliation(s)
- Arman Ahnood
- School of Engineering, RMIT University, VIC 3000, Australia
| | - Andre Chambers
- School of Physics, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Amy Gelmi
- School of Science, RMIT University, VIC 3000, Australia
| | - Ken-Tye Yong
- School of Biomedical Engineering, University of Sydney, Sydney, NSW 2006, Australia.,The University of Sydney Nano Institute, Sydney, NSW 2006, Australia.
| | - Omid Kavehei
- School of Biomedical Engineering, University of Sydney, Sydney, NSW 2006, Australia.,The University of Sydney Nano Institute, Sydney, NSW 2006, Australia.
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5
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Niederhoffer T, Vanhoestenberghe A, Lancashire HT. Methods of poly(3,4)-ethylenedioxithiophene (PEDOT) electrodeposition on metal electrodes for neural stimulation and recording. J Neural Eng 2023; 20. [PMID: 36603213 DOI: 10.1088/1741-2552/acb084] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 01/05/2023] [Indexed: 01/06/2023]
Abstract
Conductive polymers are of great interest in the field of neural electrodes because of their potential to improve the interfacial properties of electrodes. In particular, the conductive polymer poly (3,4)-ethylenedioxithiophene (PEDOT) has been widely studied for neural applications.Objective:This review compares methods for electrodeposition of PEDOT on metal neural electrodes, and analyses the effects of deposition methods on morphology and electrochemical performance.Approach:Electrochemical performances were analysed against several deposition method choices, including deposition charge density and co-ion, and correlations were explained to morphological and structural arguments as well as characterisation methods choices.Main results:Coating thickness and charge storage capacity are positively correlated with PEDOT electrodeposition charge density. We also show that PEDOT coated electrode impedance at 1 kHz, the only consistently reported impedance quantity, is strongly dependent upon electrode radius across a wide range of studies, because PEDOT coatings reduces the reactance of the complex impedance, conferring a more resistive behaviour to electrodes (at 1 kHz) dominated by the solution resistance and electrode geometry. This review also summarises how PEDOT co-ion choice affects coating structure and morphology and shows that co-ions notably influence the charge injection limit but have a limited influence on charge storage capacity and impedance. Finally we discuss the possible influence of characterisation methods to assess the robustness of comparisons between published results using different methods of characterisation.Significance:This review aims to serve as a common basis for researchers working with PEDOT by showing the effects of deposition methods on electrochemical performance, and aims to set a standard for accurate and uniform reporting of methods.
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Affiliation(s)
- Thomas Niederhoffer
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Anne Vanhoestenberghe
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Henry T Lancashire
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
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Karamali F, Behtaj S, Babaei-Abraki S, Hadady H, Atefi A, Savoj S, Soroushzadeh S, Najafian S, Nasr Esfahani MH, Klassen H. Potential therapeutic strategies for photoreceptor degeneration: the path to restore vision. J Transl Med 2022; 20:572. [PMID: 36476500 PMCID: PMC9727916 DOI: 10.1186/s12967-022-03738-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/29/2022] [Indexed: 12/12/2022] Open
Abstract
Photoreceptors (PRs), as the most abundant and light-sensing cells of the neuroretina, are responsible for converting light into electrical signals that can be interpreted by the brain. PR degeneration, including morphological and functional impairment of these cells, causes significant diminution of the retina's ability to detect light, with consequent loss of vision. Recent findings in ocular regenerative medicine have opened promising avenues to apply neuroprotective therapy, gene therapy, cell replacement therapy, and visual prostheses to the challenge of restoring vision. However, successful visual restoration in the clinical setting requires application of these therapeutic approaches at the appropriate stage of the retinal degeneration. In this review, firstly, we discuss the mechanisms of PR degeneration by focusing on the molecular mechanisms underlying cell death. Subsequently, innovations, recent developments, and promising treatments based on the stage of disorder progression are further explored. Then, the challenges to be addressed before implementation of these therapies in clinical practice are considered. Finally, potential solutions to overcome the current limitations of this growing research area are suggested. Overall, the majority of current treatment modalities are still at an early stage of development and require extensive additional studies, both pre-clinical and clinical, before full restoration of visual function in PR degeneration diseases can be realized.
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Affiliation(s)
- Fereshteh Karamali
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sanaz Behtaj
- grid.1022.10000 0004 0437 5432Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Queensland, Australia ,grid.1022.10000 0004 0437 5432Menzies Health Institute Queensland, Griffith University, Southport, QLD 4222 Australia
| | - Shahnaz Babaei-Abraki
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Hanieh Hadady
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Atefeh Atefi
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Soraya Savoj
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sareh Soroushzadeh
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Samaneh Najafian
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Mohammad Hossein Nasr Esfahani
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Henry Klassen
- grid.266093.80000 0001 0668 7243Gavin Herbert Eye Institute, Irvine, CA USA
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In Vitro Cytotoxicity of D18 and Y6 as Potential Organic Photovoltaic Materials for Retinal Prostheses. Int J Mol Sci 2022; 23:ijms23158666. [PMID: 35955800 PMCID: PMC9369111 DOI: 10.3390/ijms23158666] [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: 07/08/2022] [Revised: 07/31/2022] [Accepted: 08/02/2022] [Indexed: 02/01/2023] Open
Abstract
Millions of people worldwide are diagnosed with retinal dystrophies such as retinitis pigmentosa and age-related macular degeneration. A retinal prosthesis using organic photovoltaic (OPV) semiconductors is a promising therapeutic device to restore vision to patients at the late onset of the disease. However, an appropriate cytotoxicity approach has to be employed on the OPV materials before using them as retinal implants. In this study, we followed ISO standards to assess the cytotoxicity of D18, Y6, PFN-Br and PDIN individually, and as mixtures of D18/Y6, D18/Y6/PFN-Br and D18/Y6/PDIN. These materials were proven for their high performance as organic solar cells. Human RPE cells were put in direct and indirect contact with these materials to analyze their cytotoxicity by the MTT assay, apoptosis by flow cytometry, and measurements of cell morphology and proliferation by immunofluorescence. We also assessed electrophysiological recordings on mouse retinal explants via microelectrode arrays (MEAs) coated with D18/Y6. In contrast to PFN-Br and PDIN, all in vitro experiments show no cytotoxicity of D18 and Y6 alone or as a D18/Y6 mixture. We conclude that D18/Y6 is safe to be subsequently investigated as a retinal prosthesis.
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Remote Sensing System for Motor Nerve Impulse. SENSORS 2022; 22:s22082823. [PMID: 35458809 PMCID: PMC9027399 DOI: 10.3390/s22082823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 12/04/2022]
Abstract
In this article, we present our research achievements regarding the development of a remote sensing system for motor pulse acquisition, as a first step towards a complete neuroprosthetic arm. We present the fabrication process of an implantable electrode for nerve impulse acquisition, together with an innovative wirelessly controlled system. In our study, these were combined into an implantable device for attachment to peripheral nerves. Mechanical and biocompatibility tests were performed, as well as in vivo testing on pigs using the developed system. This testing and the experimental results are presented in a comprehensive manner, demonstrating that the system is capable of accomplishing the requirements of its designed application. Most significantly, neural electrical signals were acquired and transmitted out of the body during animal experiments, which were conducted according to ethical regulations in the field.
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Yuan B, Aziz MRF, Li S, Wu J, Li D, Li RK. An electro-spun tri-component polymer biomaterial with optoelectronic properties for neuronal differentiation. Acta Biomater 2022; 139:82-90. [PMID: 34082104 DOI: 10.1016/j.actbio.2021.05.036] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/04/2021] [Accepted: 05/20/2021] [Indexed: 12/20/2022]
Abstract
Optoelectronic biomaterials have recently emerged as a potential treatment option for neurodegenerative diseases, such as optic macular degeneration. Though initial works in the field have involved bulk heterojunctions mimicking solar panels with photovoltaics (PVs) and conductive polymers (CPs), recent developments have considered abandoning CPs in such systems. Here, we developed a simple antioxidant, biocompatible, and fibrous membrane heterojunction composed of photoactive polymer poly(3-hexylthiophene) (P3HT), polycaprolactone (PCL) and polypyrrole (PPY), to facilitate neurogenesis of PC-12 cells when photo-stimulated in vitro. The photoactive prototype, referred to as PCL-P3HT/PPY, was fabricated via polymerization of pyrrole on electro-spun PCL-P3HT nanofibers to form a membrane. Four experimental groups, namely PCL alone, PCL/PPY, PCL-P3HT and PCL-P3HT/PPY, were tested. In the absence of the CP, PCL-P3HT demonstrated lower cell survival due to increased intracellular reactive oxygen/nitrogen species production. PCL-P3HT/PPY rescued these cells by virtue of scavenging radicals, where the CP, PPY, acted as an antioxidant. Apart from having lower impedance, the material also enhanced neurogenesis of PC-12 cells when photo-stimulated, compared to the traditional PCL-P3HT. Lastly, the in vitro system with PC-12 was used to demonstrate the practicality of the material for potential use as a cellular patch in optic and nerve regeneration. This work demonstrated the importance of maintaining PV-CP heterojunctions while simultaneously providing an optoelectrical platform for neural and optical tissue engineering. STATEMENT OF SIGNIFICANCE: Regeneration and repair of injured nervous systems have always been a major clinical challenge. Stem cell therapy is a promising approach for nerve regeneration, and opto-electrical stimulation, which converts light into an electrical signal, has been shown to efficiently regulate stem cell behaviors with enhanced neurogenesis. We developed a micro-fibrous membrane, composed of photoactive polymer, P3HT, scaffold material PCL and conductive polymer PPY. Our heterojunction system improved cell survival via PPY quenching PCL-P3HT-generated cell-damaging reactive oxygen species. PPY also conducted electrons produced from light-stimulated P3HT to promote neurogenesis. This photoactive microfiber biomaterial has great potential as a highly biocompatible and efficient platform to wirelessly promote neurogenesis and survival. Our approach thus showed possibilities with respect to optical tissue engineering.
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Vajrala VS, Saunier V, Nowak LG, Flahaut E, Bergaud C, Maziz A. Nanofibrous PEDOT-Carbon Composite on Flexible Probes for Soft Neural Interfacing. Front Bioeng Biotechnol 2021; 9:780197. [PMID: 34900968 PMCID: PMC8662776 DOI: 10.3389/fbioe.2021.780197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/12/2021] [Indexed: 11/25/2022] Open
Abstract
In this study, we report a flexible implantable 4-channel microelectrode probe coated with highly porous and robust nanocomposite of poly (3,4-ethylenedioxythiophene) (PEDOT) and carbon nanofiber (CNF) as a solid doping template for high-performance in vivo neuronal recording and stimulation. A simple yet well-controlled deposition strategy was developed via in situ electrochemical polymerization technique to create a porous network of PEDOT and CNFs on a flexible 4-channel gold microelectrode probe. Different morphological and electrochemical characterizations showed that they exhibit remarkable and superior electrochemical properties, yielding microelectrodes combining high surface area, low impedance (16.8 ± 2 MΩ µm2 at 1 kHz) and elevated charge injection capabilities (7.6 ± 1.3 mC/cm2) that exceed those of pure and composite PEDOT layers. In addition, the PEDOT-CNF composite electrode exhibited extended biphasic charge cycle endurance and excellent performance under accelerated lifetime testing, resulting in a negligible physical delamination and/or degradation for long periods of electrical stimulation. In vitro testing on mouse brain slices showed that they can record spontaneous oscillatory field potentials as well as single-unit action potentials and allow to safely deliver electrical stimulation for evoking field potentials. The combined superior electrical properties, durability and 3D microstructure topology of the PEDOT-CNF composite electrodes demonstrate outstanding potential for developing future neural surface interfacing applications.
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Affiliation(s)
| | - Valentin Saunier
- Laboratory for Analysis and Architecture of Systems (LAAS), CNRS, Toulouse, France
| | - Lionel G Nowak
- Centre de Recherche Cerveau et Cognition (CerCo), CNRS, Toulouse, France
| | | | - Christian Bergaud
- Laboratory for Analysis and Architecture of Systems (LAAS), CNRS, Toulouse, France
| | - Ali Maziz
- Laboratory for Analysis and Architecture of Systems (LAAS), CNRS, Toulouse, France
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11
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Xu Y, Pang S. Microelectrode Array With Integrated Pneumatic Channels for Dynamic Control of Electrode Position in Retinal Implants. IEEE Trans Neural Syst Rehabil Eng 2021; 29:2292-2298. [PMID: 34705653 DOI: 10.1109/tnsre.2021.3123754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Retinal prostheses are biomedical devices that directly utilize electrical stimulation to create an artificial vision to help patients with retinal diseases such as retinitis pigmentosa. A major challenge in the microelectrode array (MEA) design for retinal prosthesis is to have a close topographical fit on the retinal surface. The local retinal topography can cause the electrodes in certain areas to have gaps up to several hundred micrometers from the retinal surface, resulting in impaired, or totally lost electrode functions in specific areas of the MEA. In this manuscript, an MEA with dynamically controlled electrode positions was proposed to reduce the electrode-retina distance and eliminate areas with poor contact after implantation. The MEA prototype had a polydimethylsiloxane and polyimide hybrid flexible substrate with gold interconnect lines and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate electrodes. Ring shaped counter electrodes were placed around the main electrodes to measure the distance between the electrode and the model retinal surface in real time. The results showed that this MEA design could reduce electrode-retina distance up to [Formula: see text] with 200 kPa pressure. Meanwhile, the impedance between the main and counter electrodes increased with smaller electrode-model retinal surface distance. Thus, the change of electrode-counter electrode impedance could be used to measure the separation gap and to confirm successful electrode contact without the need of optical coherence tomography scan. The amplitude of the stimulation signal on the model retinal surface with originally poor contact could be significantly improved after pressure was applied to reduce the gap.
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12
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Zheng XS, Yang Q, Vazquez AL, Tracy Cui X. Imaging the Efficiency of Poly(3,4-ethylenedioxythiophene) Doped with Acid-Functionalized Carbon Nanotube and Iridium Oxide Electrode Coatings for Microstimulation. ADVANCED NANOBIOMED RESEARCH 2021; 1:2000092. [PMID: 34746928 PMCID: PMC8552016 DOI: 10.1002/anbr.202000092] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/18/2021] [Indexed: 12/02/2022] Open
Abstract
Electrical microstimulation has shown promise in restoring neural deficits in humans. Electrodes coated with materials like the conducting polymer poly(3,4-ethylenedioxythiophene) doped with acid-functionalized carbon nanotubes (PEDOT/CNTs, or PC) exhibit superior charge injection than traditional metals like platinum. However, the stimulation performance of PC remains to be fully characterized. Advanced imaging techniques and transgenic tools allow for real-time observations of neural activity in vivo. Herein, microelectrodes coated with PC and iridium oxide (IrOx) (a commonly used high-charge-injection material) are implanted in GCaMP6s mice and electrical stimulation is applied while imaging neuronal calcium responses. Results show that PC-coated electrodes stimulate more intense and broader GCaMP responses than IrOx. Two-photon microscopy reveals that PC-coated electrodes activate significantly more neuronal soma and neuropil than IrOx-coated electrodes in constant-voltage stimulation and significantly more neuronal soma in constant-current stimulation. Furthermore, with the same injected charge, both materials activate more spatially confined neural elements with shorter pulses than longer pulses, providing a means to tune stimulation selectivity. Finite element analyses reveal that the PC coating creates a denser and nonuniform electric field, increasing the likelihood of activating nearby neural elements. PC coating can significantly improve energy efficiency for electrical stimulation applications.
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Affiliation(s)
- Xin S. Zheng
- Department of BioengineeringUniversity of Pittsburgh3501 Fifth Ave.PittsburghPA15213USA
| | - Qianru Yang
- Department of BioengineeringUniversity of Pittsburgh3501 Fifth Ave.PittsburghPA15213USA
| | - Alberto L. Vazquez
- Departments of Radiology and BioengineeringUniversity of Pittsburgh3025 E. Carson St.PittsburghPA15203USA
| | - Xinyan Tracy Cui
- Department of BioengineeringUniversity of Pittsburgh3501 Fifth Ave.PittsburghPA15213USA
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13
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Corna A, Ramesh P, Jetter F, Lee MJ, Macke JH, Zeck G. Discrimination of simple objects decoded from the output of retinal ganglion cells upon sinusoidal electrical stimulation. J Neural Eng 2021; 18. [PMID: 34049288 DOI: 10.1088/1741-2552/ac0679] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 05/28/2021] [Indexed: 11/12/2022]
Abstract
Objective. Most neuroprosthetic implants employ pulsatile square-wave electrical stimuli, which are significantly different from physiological inter-neuronal communication. In case of retinal neuroprosthetics, which use a certain type of pulsatile stimuli, reliable object and contrast discrimination by implanted blind patients remained challenging. Here we investigated to what extent simple objects can be discriminated from the output of retinal ganglion cells (RGCs) upon sinusoidal stimulation.Approach. Spatially confined objects were formed by different combinations of 1024 stimulating microelectrodes. The RGC activity in theex vivoretina of photoreceptor-degenerated mouse, of healthy mouse or of primate was recorded simultaneously using an interleaved recording microelectrode array implemented in a CMOS-based chip.Main results. We report that application of sinusoidal electrical stimuli (40 Hz) in epiretinal configuration instantaneously and reliably modulates the RGC activity in spatially confined areas at low stimulation threshold charge densities (40 nC mm-2). Classification of overlapping but spatially displaced objects (1° separation) was achieved by distinct spiking activity of selected RGCs. A classifier (regularized logistic regression) discriminated spatially displaced objects (size: 5.5° or 3.5°) with high accuracy (90% or 62%). Stimulation with low artificial contrast (10%) encoded by different stimulus amplitudes generated RGC activity, which was classified with an accuracy of 80% for large objects (5.5°).Significance. We conclude that time-continuous smooth-wave stimulation provides robust, localized neuronal activation in photoreceptor-degenerated retina, which may enable future artificial vision at high temporal, spatial and contrast resolution.
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Affiliation(s)
- Andrea Corna
- Neurophysics, NMI Natural and Medical Sciences Institute at the University Tübingen, Reutlingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Graduate School of Neural Information Processing/International Max Planck Research School, Tübingen, Germany.,Biomedical Electronics and Systems, EMCE Institute, TU Wien, Wien, Austria
| | - Poornima Ramesh
- Computational Neuroengineering, Technical University München, München, Germany.,Machine Learning in Science, University of Tübingen, Tübingen, Germany
| | - Florian Jetter
- Neurophysics, NMI Natural and Medical Sciences Institute at the University Tübingen, Reutlingen, Germany.,Graduate School of Neural Information Processing/International Max Planck Research School, Tübingen, Germany
| | - Meng-Jung Lee
- Neurophysics, NMI Natural and Medical Sciences Institute at the University Tübingen, Reutlingen, Germany.,Graduate School of Neural Information Processing/International Max Planck Research School, Tübingen, Germany
| | - Jakob H Macke
- Computational Neuroengineering, Technical University München, München, Germany.,Machine Learning in Science, University of Tübingen, Tübingen, Germany.,MPI for Intelligent Systems, Tübingen, Germany
| | - Günther Zeck
- Neurophysics, NMI Natural and Medical Sciences Institute at the University Tübingen, Reutlingen, Germany.,Biomedical Electronics and Systems, EMCE Institute, TU Wien, Wien, Austria
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14
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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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15
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Abstract
This perspective article describes the application opportunities of carbon nanotube (CNT) films for the energy sector. Up to date progress in this regard is illustrated with representative examples of a wide range of energy management and transformation studies employing CNT ensembles. Firstly, this paper features an overview of how such macroscopic networks from nanocarbon can be produced. Then, the capabilities for their application in specific energy-related scenarios are described. Among the highlighted cases are conductive coatings, charge storage devices, thermal interface materials, and actuators. The selected examples demonstrate how electrical, thermal, radiant, and mechanical energy can be converted from one form to another using such formulations based on CNTs. The article is concluded with a future outlook, which anticipates the next steps which the research community will take to bring these concepts closer to implementation.
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16
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Chang AY, Liu X, Pei Y, Gong C, Arumugam PU, Wang S. Dopamine sensing with robust carbon nanotube implanted polymer micropillar array electrodes fabricated by coupling micromolding and infiltration coating processes. Electrochim Acta 2021. [DOI: 10.1016/j.electacta.2020.137632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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17
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Borah R, Ingavle GC, Kumar A, Sandeman SR, Mikhalovsky SV. Surface-Functionalized Conducting Nanofibers for Electrically Stimulated Neural Cell Function. Biomacromolecules 2021; 22:594-611. [PMID: 33448795 DOI: 10.1021/acs.biomac.0c01445] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Strategies involving the inclusion of cell-instructive chemical and topographical cues to smart biomaterials in combination with a suitable physical stimulus may be beneficial to enhance nerve-regeneration rate. In this regard, we investigated the surface functionalization of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV)-based electroconductive electrospun nanofibers coupled with externally applied electrical stimulus for accelerated neuronal growth potential. In addition, the voltage-dependent conductive mechanism of the nanofibers was studied in depth to interlink intrinsic conductive properties with electrically stimulated neuronal expressions. Surface functionalization was accomplished using 3-aminopropyltriethoxysilane (APTES) and 1,6-hexanediamine (HDA) as an alternative to costly biomolecule coating (e.g., collagen) for cell adhesion. The nanofibers were uniform, porous, electrically conductive, mechanically strong, and stable under physiological conditions. Surface amination boosted biocompatibility, 3T3 cell adhesion, and spreading, while the neuronal model rat PC12 cell line showed better differentiation on surface-functionalized mats compared to nonfunctionalized mats. When coupled with electrical stimulation (ES), these mats showed comparable or faster neurite formation and elongation than the collagen-coated mats with no-ES conditions. The findings indicate that surface amination in combination with ES may provide an improved strategy to faster nerve regeneration using MEH-PPV-based neural scaffolds.
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Affiliation(s)
- Rajiv Borah
- Life Sciences Division, Institute of Advanced Study in Science & Technology, Guwahati 781035, India
| | - Ganesh C Ingavle
- Symbiosis Centre for Stem Cell Research, Symbiosis International (Deemed University), Pune 412115, India
| | - Ashok Kumar
- Materials Research Laboratory, Department of Physics, Tezpur University, Tezpur 784028, India
| | - Susan R Sandeman
- Biomaterials and Medical Devices Research Group, School of Pharmacy and Biomolecular Sciences, Huxley Building, University of Brighton, Brighton BN2 4GJ, United Kingdom
| | - Sergey V Mikhalovsky
- ANAMAD Ltd, Sussex Innovation Centre, Science Park Square, Falmer, Brighton BN1 9SB, United Kingdom.,Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 17, General Naumov street, Kyiv 03164, Ukraine
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18
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Krukiewicz K, Britton J, Więcławska D, Skorupa M, Fernandez J, Sarasua JR, Biggs MJP. Electrical percolation in extrinsically conducting, poly(ε-decalactone) composite neural interface materials. Sci Rep 2021; 11:1295. [PMID: 33446813 PMCID: PMC7809477 DOI: 10.1038/s41598-020-80361-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/18/2020] [Indexed: 11/08/2022] Open
Abstract
By providing a bidirectional communication channel between neural tissues and a biomedical device, it is envisaged that neural interfaces will be fundamental in the future diagnosis and treatment of neurological disorders. Due to the mechanical mismatch between neural tissue and metallic neural electrodes, soft electrically conducting materials are of great benefit in promoting chronic device functionality. In this study, carbon nanotubes (CNT), silver nanowires (AgNW) and poly(hydroxymethyl 3,4-ethylenedioxythiophene) microspheres (MSP) were employed as conducting fillers within a poly(ε-decalactone) (EDL) matrix, to form a soft and electrically conducting composite. The effect of a filler type on the electrical percolation threshold, and composite biocompatibility was investigated in vitro. EDL-based composites exhibited favourable electrochemical characteristics: EDL/CNT-the lowest film resistance (1.2 ± 0.3 kΩ), EDL/AgNW-the highest charge storage capacity (10.7 ± 0.3 mC cm- 2), and EDL/MSP-the highest interphase capacitance (1478.4 ± 92.4 µF cm-2). All investigated composite surfaces were found to be biocompatible, and to reduce the presence of reactive astrocytes relative to control electrodes. The results of this work clearly demonstrated the ability of high aspect ratio structures to form an extended percolation network within a polyester matrix, resulting in the formulation of composites with advantageous mechanical, electrochemical and biocompatibility properties.
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Affiliation(s)
- Katarzyna Krukiewicz
- Centre for Research in Medical Devices, National University of Ireland, Newcastle Road, Galway, H91 W2TY, Ireland.
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M.Strzody 9, 44-100, Gliwice, Poland.
| | - James Britton
- Centre for Research in Medical Devices, National University of Ireland, Newcastle Road, Galway, H91 W2TY, Ireland
| | - Daria Więcławska
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M.Strzody 9, 44-100, Gliwice, Poland
| | - Małgorzata Skorupa
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M.Strzody 9, 44-100, Gliwice, Poland
| | - Jorge Fernandez
- Department of Mining-Metallurgy Engineering and Materials Science, School of Engineering, POLYMAT, University of the Basque Country (UPV/EHU), Alameda de Urquijo s/n, 48013, Bilbao, Spain
- Polimerbio, S.L, Paseo Mikeletegi 83, 20009, Donostia-San Sebastian, Spain
| | - Jose-Ramon Sarasua
- Department of Mining-Metallurgy Engineering and Materials Science, School of Engineering, POLYMAT, University of the Basque Country (UPV/EHU), Alameda de Urquijo s/n, 48013, Bilbao, Spain
| | - Manus J P Biggs
- Centre for Research in Medical Devices, National University of Ireland, Newcastle Road, Galway, H91 W2TY, Ireland
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19
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Mierzejewski M, Steins H, Kshirsagar P, Jones PD. The noise and impedance of microelectrodes. J Neural Eng 2020; 17:052001. [PMID: 33055360 DOI: 10.1088/1741-2552/abb3b4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE While the positive correlation between impedance and noise of microelectrodes is well known, their quantitative relationship is too rarely described. Knowledge of this relationship provides useful information for both microsystems engineers and electrophysiologists. APPROACH We discuss the physical basis of noise in recordings with microelectrodes, and compare measurements of impedance spectra to noise of microelectrodes. MAIN RESULTS Microelectrode recordings intrinsically include thermal noise, [Formula: see text], with the real component of impedance integrated over the recording frequency band. Impedance spectroscopy allows the quantitative prediction of thermal noise. Optimization of microelectrode noise should also consider the contribution of amplifier noise. These measures enable a quantitative evaluation of microelectrodes' recording quality which is more informative than common but limited comparisons based on the impedance magnitude at 1 kHz. SIGNIFICANCE Improved understanding of the origin of microelectrode noise will support efforts to produce smaller yet low noise microelectrodes, capable of recording from higher numbers of neurons. This tutorial is relevant for single microelectrodes, tetrodes, neural probes and microelectrode arrays, whether used in vitro or in vivo.
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Affiliation(s)
- Michael Mierzejewski
- NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, Germany
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20
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Wang Z, Cui W. Two Sides of Electrospun Fiber in Promoting and Inhibiting Biomedical Processes. ADVANCED THERAPEUTICS 2020. [DOI: 10.1002/adtp.202000096] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Zhen Wang
- Shanghai Institute of Traumatology and Orthopaedics Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases Ruijin Hospital Shanghai Jiao Tong University School of Medicine 197 Ruijin 2nd Road Shanghai 200025 P. R. China
| | - Wenguo Cui
- Shanghai Institute of Traumatology and Orthopaedics Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases Ruijin Hospital Shanghai Jiao Tong University School of Medicine 197 Ruijin 2nd Road Shanghai 200025 P. R. China
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21
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Parashar K, Prajapati D, McIntyre R, Kandasubramanian B. Advancements in Biological Neural Interfaces Using Conducting Polymers: A Review. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c00174] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Kashish Parashar
- Nanofabrication and Characterization Lab, Centre for Converging Technologies, University of Rajasthan, JLN Marg, Jaipur-302004, India
| | - Deepak Prajapati
- Material Science and Engineering, Indian Institute of Technology, Gandhinagar, Gujarat 382355, India
| | | | - Balasubramanian Kandasubramanian
- Nano Surface Texturing Lab, Dept. of Metallurgical and Materials Engineering, Defence Institute of Advanced Technology (DIAT), Ministry of Defence, DRDO, Girinagar, Pune-411025, India
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22
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Conducting Polymer-Based Composite Materials for Therapeutic Implantations: From Advanced Drug Delivery System to Minimally Invasive Electronics. INT J POLYM SCI 2020. [DOI: 10.1155/2020/5659682] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Conducting polymer-based composites have recently becoming popular in both academic research and industrial practices due to their high conductivity, ease of process, and tunable electrical properties. The multifunctional conducting polymer-based composites demonstrated great application potential for in vivo therapeutics and implantable electronics, including drug delivery, neural interfacing, and minimally invasive electronics. In this review article, the state-of-the-art conducting polymer-based composites in the mentioned biological fields are discussed and summarized. The recent progress on the synthesis, structure, properties, and application of the conducting polymer-based composites is presented, aimed at revealing the structure-property relationship and the corresponding functional applications of the conducting polymer-based composites. Furthermore, key issues and challenges regarding the implantation performance of these composites are highlighted in this paper.
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23
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Yan H, Wang Y, Li L, Zhou X, Shi X, Wei Y, Zhang P. A micropatterned conductive electrospun nanofiber mesh combined with electrical stimulation for synergistically enhancing differentiation of rat neural stem cells. J Mater Chem B 2020; 8:2673-2688. [DOI: 10.1039/c9tb02864a] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The micropatterned conductive nanofiber mesh combined with ES effectively facilitates the differentiation of NSCs into neuron and suppresses the formation of astrocytes.
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Affiliation(s)
- Huanhuan Yan
- Key Laboratory of Polymer Ecomaterials
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun 130022
- P. R. China
| | - Yu Wang
- Key Laboratory of Polymer Ecomaterials
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun 130022
- P. R. China
| | - Linlong Li
- Key Laboratory of Polymer Ecomaterials
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun 130022
- P. R. China
| | - Xiaosong Zhou
- Key Laboratory of Polymer Ecomaterials
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun 130022
- P. R. China
| | - Xincui Shi
- Key Laboratory of Polymer Ecomaterials
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun 130022
- P. R. China
| | - Yen Wei
- Department of Chemistry
- Tsinghua University
- Beijing 100084
- P. R. China
| | - Peibiao Zhang
- Key Laboratory of Polymer Ecomaterials
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun 130022
- P. R. China
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24
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Chenais NAL, Leccardi MJIA, Ghezzi D. Capacitive-like photovoltaic epiretinal stimulation enhances and narrows the network-mediated activity of retinal ganglion cells by recruiting the lateral inhibitory network. J Neural Eng 2019; 16:066009. [DOI: 10.1088/1741-2552/ab3913] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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25
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Gulino M, Kim D, Pané S, Santos SD, Pêgo AP. Tissue Response to Neural Implants: The Use of Model Systems Toward New Design Solutions of Implantable Microelectrodes. Front Neurosci 2019; 13:689. [PMID: 31333407 PMCID: PMC6624471 DOI: 10.3389/fnins.2019.00689] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/18/2019] [Indexed: 01/28/2023] Open
Abstract
The development of implantable neuroelectrodes is advancing rapidly as these tools are becoming increasingly ubiquitous in clinical practice, especially for the treatment of traumatic and neurodegenerative disorders. Electrodes have been exploited in a wide number of neural interface devices, such as deep brain stimulation, which is one of the most successful therapies with proven efficacy in the treatment of diseases like Parkinson or epilepsy. However, one of the main caveats related to the clinical application of electrodes is the nervous tissue response at the injury site, characterized by a cascade of inflammatory events, which culminate in chronic inflammation, and, in turn, result in the failure of the implant over extended periods of time. To overcome current limitations of the most widespread macroelectrode based systems, new design strategies and the development of innovative materials with superior biocompatibility characteristics are currently being investigated. This review describes the current state of the art of in vitro, ex vivo, and in vivo models available for the study of neural tissue response to implantable microelectrodes. We particularly highlight new models with increased complexity that closely mimic in vivo scenarios and that can serve as promising alternatives to animal studies for investigation of microelectrodes in neural tissues. Additionally, we also express our view on the impact of the progress in the field of neural tissue engineering on neural implant research.
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Affiliation(s)
- Maurizio Gulino
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- FEUP – Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
| | - Donghoon Kim
- Multi-Scale Robotics Lab (MSRL), Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Zurich, Switzerland
| | - Salvador Pané
- Multi-Scale Robotics Lab (MSRL), Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Zurich, Switzerland
| | - Sofia Duque Santos
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - Ana Paula Pêgo
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- FEUP – Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
- ICBAS – Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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Rathbun DL, Ghorbani N, Shabani H, Zrenner E, Hosseinzadeh Z. Spike-triggered average electrical stimuli as input filters for bionic vision—a perspective. J Neural Eng 2018; 15:063002. [DOI: 10.1088/1741-2552/aae493] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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27
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Borah R, Ingavle GC, Sandeman SR, Kumar A, Mikhalovsky SV. Amine-Functionalized Electrically Conductive Core-Sheath MEH-PPV:PCL Electrospun Nanofibers for Enhanced Cell-Biomaterial Interactions. ACS Biomater Sci Eng 2018; 4:3327-3346. [PMID: 33435069 DOI: 10.1021/acsbiomaterials.8b00624] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the present study, a conducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) along with a biodegradable polymer poly(ε-caprolactone) (PCL) was used to prepare an electrically conductive, biocompatible, bioactive, and biodegradable nanofibrous scaffold for possible use in neural tissue engineering applications. Core-sheath electrospun nanofibers of PCL as the core and MEH-PPV as the sheath, were surface-functionalized with (3-aminopropyl) triethoxysilane (APTES) and 1,6-hexanediamine to obtain amine-functionalized surface to facilitate cell-biomaterial interactions with the aim of replacing the costly biomolecules such as collagen, fibronectin, laminin, and arginyl-glycyl-aspartic acid (RGD) peptide for surface modification. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed the formation of core-sheath morphology of the electrospun nanofibers, whereas Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) revealed successful incorporation of amine functionality after surface functionalization. Adhesion, spreading, and proliferation of 3T3 fibroblasts were enhanced on the surface-functionalized electrospun meshes, whereas the neuronal model rat pheochromocytoma 12 (PC12) cells also adhered and differentiated into sympathetic neurons on these meshes. Under a constant electric field of 500 mV for 2 h/day for 3 consecutive days, the PC12 cells displayed remarkable improvement in the neurite formation and outgrowth on the surface-functionalized meshes that was comparable to those on the collagen-coated meshes under no electrical signal. Electrical stimulation studies further demonstrated that electrically stimulated PC12 cells cultured on collagen I coated meshes yielded more and longer neurites than those of the unstimulated cells on the same scaffolds. The enhanced neurite growth and differentiation suggest the potential use of these scaffolds for neural tissue engineering applications.
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Affiliation(s)
- Rajiv Borah
- Materials Research Laboratory, Department of Physics, Tezpur University, Tezpur 784028, India
| | - Ganesh C Ingavle
- Biomaterials and Medical Devices Research Group, School of Pharmacy and Biomolecular Sciences, Huxley Building, University of Brighton, Brighton BN2 4GJ, United Kingdom.,Symbiosis Centre for Stem Cell Research, Symbiosis School of Biological Sciences, Symbiosis International University, Pune 412115, India
| | - Susan R Sandeman
- Biomaterials and Medical Devices Research Group, School of Pharmacy and Biomolecular Sciences, Huxley Building, University of Brighton, Brighton BN2 4GJ, United Kingdom
| | - Ashok Kumar
- Materials Research Laboratory, Department of Physics, Tezpur University, Tezpur 784028, India
| | - Sergey V Mikhalovsky
- ANAMAD Ltd., Sussex Innovation Centre, Science Park Square, Falmer, Brighton BN1 9SB, United Kingdom.,SD Asfendiyarov Kazakh National Medical University, Tole Bi Street 94, Almaty 050000, Kazakhstan
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Lee JI, Im M. Non-rectangular waveforms are more charge-efficient than rectangular one in eliciting network-mediated responses of ON type retinal ganglion cells. J Neural Eng 2018; 15:055004. [PMID: 30018183 DOI: 10.1088/1741-2552/aad416] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE For individuals blinded by outer retinal degenerative diseases, retinal prostheses would be a promising option to restore sight. Unfortunately, however, the best performance of existing devices is still far removed from normal vision. One possible reason for the shortcoming is thought to be suboptimal stimulation conditions such as the waveform shape of electric stimulus. In this study, we explored the effects of varying waveforms on network-mediated responses arising in retinal ganglion cells (RGCs). APPROACH We used a cell-attached patch clamp technique to record RGC spiking activities in the isolated mouse retina. ON alpha RGCs were targeted by soma size and their light responses to stationary spot flashes. Spiking in targeted RGCs was measured in response to an epiretinally-delivered cathodal current pulse in four waveforms: rectangular, center triangular, increasing and decreasing ramp shapes. Each waveform was tested at three durations (20, 10, and 5 ms) with adjusted amplitude for a range of total charges (50-400 nC). MAIN RESULTS ON alpha RGCs always generated two bursts of spikes in responses to all stimuli conditions we tested. However, at a given charge, effects of differing waveforms were distinct in the two bursts. For the first burst, the increasing ramp was most effective among the four waveforms (p < 0.05 for all pairwise comparisons with other waveforms). For example, in responses arising from 20 ms-long stimuli, the increasing ramp evoked ~44% more spikes on average than the rectangular shape which is the typical choice of neural stimulation. Also, the rectangular stimulus evoked the weakest response in the delayed burst arising from pulses of every duration. For instance, 20 ms-long stimuli in the three non-rectangular waveforms showed ~23% or more increment in spike counts compared to response arising from the rectangular one; but there was no statistical difference in response magnitudes across the non-rectangular waveforms. SIGNIFICANCE Although the rectangular waveform has been primarily used in retinal prostheses our results indicate that rectangular stimulus is not optimal for network-mediated responses of ON alpha RGCs. Instead, non-rectangular waveforms evoke stronger responses at a given charge, indicating higher charge-efficiency. Therefore, non-rectangular waveforms are expected to enhance clinical efficacy of retinal prostheses.
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Affiliation(s)
- Jae-Ik Lee
- Department of Ophthalmology, Henry Ford Health System, 1 Ford Place, Detroit, MI 48202, United States of America. Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, United States of America
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Corna A, Herrmann T, Zeck G. Electrode-size dependent thresholds in subretinal neuroprosthetic stimulation. J Neural Eng 2018; 15:045003. [DOI: 10.1088/1741-2552/aac1c8] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Young AT, Cornwell N, Daniele MA. Neuro-Nano Interfaces: Utilizing Nano-Coatings and Nanoparticles to Enable Next-Generation Electrophysiological Recording, Neural Stimulation, and Biochemical Modulation. ADVANCED FUNCTIONAL MATERIALS 2018; 28:1700239. [PMID: 33867903 PMCID: PMC8049593 DOI: 10.1002/adfm.201700239] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Neural interfaces provide a window into the workings of the nervous system-enabling both biosignal recording and modulation. Traditionally, neural interfaces have been restricted to implanted electrodes to record or modulate electrical activity of the nervous system. Although these electrode systems are both mechanically and operationally robust, they have limited utility due to the resultant macroscale damage from invasive implantation. For this reason, novel nanomaterials are being investigated to enable new strategies to chronically interact with the nervous system at both the cellular and network level. In this feature article, the use of nanomaterials to improve current electrophysiological interfaces, as well as enable new nano-interfaces to modulate neural activity via alternative mechanisms, such as remote transduction of electromagnetic fields are explored. Specifically, this article will review the current use of nanoparticle coatings to enhance electrode function, then an analysis of the cutting-edge, targeted nanoparticle technologies being utilized to interface with both the electrophysiological and biochemical behavior of the nervous system will be provided. Furthermore, an emerging, specialized-use case for neural interfaces will be presented: the modulation of the blood-brain barrier.
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Affiliation(s)
- Ashlyn T Young
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, and North Carolina State University, 911 Oval Dr., Raleigh, NC 27695, USA
| | - Neil Cornwell
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, and North Carolina State University, 911 Oval Dr., Raleigh, NC 27695, USA
| | - Michael A Daniele
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, and North Carolina State University, 911 Oval Dr., Raleigh, NC 27695, USA
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Borah R, Ingavle GC, Sandeman SR, Kumar A, Mikhalovsky S. Electrically conductive MEH-PPV:PCL electrospun nanofibres for electrical stimulation of rat PC12 pheochromocytoma cells. Biomater Sci 2018; 6:2342-2359. [DOI: 10.1039/c8bm00559a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrically conductive, porous, mechanically strong and bioactive electrospun MEH-PPV:PCL nanofibres with blended and core-sheath formulations for enhanced neurite formation and neurite outgrowth.
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Affiliation(s)
- Rajiv Borah
- Materials Research Laboratory
- Department of Physics
- Tezpur University
- Tezpur
- India
| | - Ganesh C. Ingavle
- Biomaterials and Medical Devices Research Group
- School of Pharmacy and Biomolecular Sciences
- Huxley Building
- University of Brighton
- Brighton BN2 4GJ
| | - Susan R. Sandeman
- Biomaterials and Medical Devices Research Group
- School of Pharmacy and Biomolecular Sciences
- Huxley Building
- University of Brighton
- Brighton BN2 4GJ
| | - Ashok Kumar
- Materials Research Laboratory
- Department of Physics
- Tezpur University
- Tezpur
- India
| | - Sergey Mikhalovsky
- Biomaterials and Medical Devices Research Group
- School of Pharmacy and Biomolecular Sciences
- Huxley Building
- University of Brighton
- Brighton BN2 4GJ
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32
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Liu Z, Dong L, Cheng K, Luo Z, Weng W. Charge injection based electrical stimulation on polypyrrole planar electrodes to regulate cellular osteogenic differentiation. RSC Adv 2018; 8:18470-18479. [PMID: 35541122 PMCID: PMC9080618 DOI: 10.1039/c8ra02601g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/13/2018] [Indexed: 01/08/2023] Open
Abstract
This study reveals that the Qinj on electrodes is a more significant factor than applied voltage for electrical stimulation to regulate cellular osteogenic differentiation, and the charge injection capacity can be tuned by thickness of Ppy.
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Affiliation(s)
- Zongguang Liu
- School of Materials Science and Engineering
- State Key Laboratory of Silicon Materials
- Zhejiang University
- Hangzhou 310027
- China
| | - Lingqing Dong
- School of Materials Science and Engineering
- State Key Laboratory of Silicon Materials
- Zhejiang University
- Hangzhou 310027
- China
| | - Kui Cheng
- School of Materials Science and Engineering
- State Key Laboratory of Silicon Materials
- Zhejiang University
- Hangzhou 310027
- China
| | - Zhongkuan Luo
- Zhejiang-California International NanoSystems Institute
- Hangzhou 310058
- China
| | - Wenjian Weng
- School of Materials Science and Engineering
- State Key Laboratory of Silicon Materials
- Zhejiang University
- Hangzhou 310027
- China
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A very large-scale microelectrode array for cellular-resolution electrophysiology. Nat Commun 2017; 8:1802. [PMID: 29176752 PMCID: PMC5702607 DOI: 10.1038/s41467-017-02009-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 11/01/2017] [Indexed: 11/24/2022] Open
Abstract
In traditional electrophysiology, spatially inefficient electronics and the need for tissue-to-electrode proximity defy non-invasive interfaces at scales of more than a thousand low noise, simultaneously recording channels. Using compressed sensing concepts and silicon complementary metal-oxide-semiconductors (CMOS), we demonstrate a platform with 65,536 simultaneously recording and stimulating electrodes in which the per-electrode electronics consume an area of 25.5 μm by 25.5 μm. Application of this platform to mouse retinal studies is achieved with a high-performance processing pipeline with a 1 GB/s data rate. The platform records from 65,536 electrodes concurrently with a ~10 µV r.m.s. noise; senses spikes from more than 34,000 electrodes when recording across the entire retina; automatically sorts and classifies greater than 1700 neurons following visual stimulation; and stimulates individual neurons using any number of the 65,536 electrodes while observing spikes over the entire retina. The approaches developed here are applicable to other electrophysiological systems and electrode configurations. Large electronics limit low-noise, non-invasive electrophysiological measurements to a thousand simultaneously recording channels. Here the authors build an array of 65k simultaneously recording and stimulating electrodes and use it to sort and classify single neurons across the entire mouse retina.
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Barriga-Rivera A, Bareket L, Goding J, Aregueta-Robles UA, Suaning GJ. Visual Prosthesis: Interfacing Stimulating Electrodes with Retinal Neurons to Restore Vision. Front Neurosci 2017; 11:620. [PMID: 29184478 PMCID: PMC5694472 DOI: 10.3389/fnins.2017.00620] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/23/2017] [Indexed: 01/06/2023] Open
Abstract
The bypassing of degenerated photoreceptors using retinal neurostimulators is helping the blind to recover functional vision. Researchers are investigating new ways to improve visual percepts elicited by these means as the vision produced by these early devices remain rudimentary. However, several factors are hampering the progression of bionic technologies: the charge injection limits of metallic electrodes, the mechanical mismatch between excitable tissue and the stimulating elements, neural and electric crosstalk, the physical size of the implanted devices, and the inability to selectively activate different types of retinal neurons. Electrochemical and mechanical limitations are being addressed by the application of electromaterials such as conducting polymers, carbon nanotubes and nanocrystalline diamonds, among other biomaterials, to electrical neuromodulation. In addition, the use of synthetic hydrogels and cell-laden biomaterials is promising better interfaces, as it opens a door to establishing synaptic connections between the electrode material and the excitable cells. Finally, new electrostimulation approaches relying on the use of high-frequency stimulation and field overlapping techniques are being developed to better replicate the neural code of the retina. All these elements combined will bring bionic vision beyond its present state and into the realm of a viable, mainstream therapy for vision loss.
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Affiliation(s)
- Alejandro Barriga-Rivera
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
- Faculty of Engineering and Information Technologies, University of Sydney, Sydney, NSW, Australia
- Division of Neuroscience, University Pablo de Olavide, Sevilla, Spain
| | - Lilach Bareket
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
- Faculty of Engineering and Information Technologies, University of Sydney, Sydney, NSW, Australia
| | - Josef Goding
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | | | - Gregg J. Suaning
- Faculty of Engineering and Information Technologies, University of Sydney, Sydney, NSW, Australia
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Jalligampala A, Sekhar S, Zrenner E, Rathbun DL. Optimal voltage stimulation parameters for network-mediated responses in wild type and rd10 mouse retinal ganglion cells. J Neural Eng 2017; 14:026004. [PMID: 28155848 DOI: 10.1088/1741-2552/14/2/026004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
To further improve the quality of visual percepts elicited by microelectronic retinal prosthetics, substantial efforts have been made to understand how retinal neurons respond to electrical stimulation. It is generally assumed that a sufficiently strong stimulus will recruit most retinal neurons. However, recent evidence has shown that the responses of some retinal neurons decrease with excessively strong stimuli (a non-monotonic response function). Therefore, it is necessary to identify stimuli that can be used to activate the majority of retinal neurons even when such non-monotonic cells are part of the neuronal population. Taking these non-monotonic responses into consideration, we establish the optimal voltage stimulation parameters (amplitude, duration, and polarity) for epiretinal stimulation of network-mediated (indirect) ganglion cell responses. We recorded responses from 3958 mouse retinal ganglion cells (RGCs) in both healthy (wild type, WT) and a degenerating (rd10) mouse model of retinitis pigmentosa-using flat-mounted retina on a microelectrode array. Rectangular monophasic voltage-controlled pulses were presented with varying voltage, duration, and polarity. We found that in 4-5 weeks old rd10 mice the RGC thresholds were comparable to those of WT. There was a marked response variability among mouse RGCs. To account for this variability, we interpolated the percentage of RGCs activated at each point in the voltage-polarity-duration stimulus space, thus identifying the optimal voltage-controlled pulse (-2.4 V, 0.88 ms). The identified optimal voltage pulse can activate at least 65% of potentially responsive RGCs in both mouse strains. Furthermore, this pulse is well within the range of stimuli demonstrated to be safe and effective for retinal implant patients. Such optimized stimuli and the underlying method used to identify them support a high yield of responsive RGCs and will serve as an effective guideline for future in vitro investigations of retinal electrostimulation by establishing standard stimuli for each unique experimental condition.
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Affiliation(s)
- Archana Jalligampala
- Institute for Ophthalmic Research, Eberhard Karls University, D-72076 Tübingen, Germany. Werner Reichardt Centre for Integrative Neuroscience (CIN), D-72076 Tübingen, Germany. Graduate Training Center of Neuroscience/International Max Planck Research School, D-72074 Tübingen, Germany
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36
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Zhao Z, Gong R, Zheng L, Wang J. In Vivo Neural Recording and Electrochemical Performance of Microelectrode Arrays Modified by Rough-Surfaced AuPt Alloy Nanoparticles with Nanoporosity. SENSORS (BASEL, SWITZERLAND) 2016; 16:E1851. [PMID: 27827893 PMCID: PMC5134510 DOI: 10.3390/s16111851] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 10/18/2016] [Accepted: 10/28/2016] [Indexed: 11/16/2022]
Abstract
In order to reduce the impedance and improve in vivo neural recording performance of our developed Michigan type silicon electrodes, rough-surfaced AuPt alloy nanoparticles with nanoporosity were deposited on gold microelectrode sites through electro-co-deposition of Au-Pt-Cu alloy nanoparticles, followed by chemical dealloying Cu. The AuPt alloy nanoparticles modified gold microelectrode sites were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and in vivo neural recording experiment. The SEM images showed that the prepared AuPt alloy nanoparticles exhibited cauliflower-like shapes and possessed very rough surfaces with many different sizes of pores. Average impedance of rough-surfaced AuPt alloy nanoparticles modified sites was 0.23 MΩ at 1 kHz, which was only 4.7% of that of bare gold microelectrode sites (4.9 MΩ), and corresponding in vitro background noise in the range of 1 Hz to 7500 Hz decreased to 7.5 μ V rms from 34.1 μ V rms at bare gold microelectrode sites. Spontaneous spike signal recording was used to evaluate in vivo neural recording performance of modified microelectrode sites, and results showed that rough-surfaced AuPt alloy nanoparticles modified microelectrode sites exhibited higher average spike signal-to-noise ratio (SNR) of 4.8 in lateral globus pallidus (GPe) due to lower background noise compared to control microelectrodes. Electro-co-deposition of Au-Pt-Cu alloy nanoparticles combined with chemical dealloying Cu was a convenient way for increasing the effective surface area of microelectrode sites, which could reduce electrode impedance and improve the quality of in vivo spike signal recording.
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Affiliation(s)
- Zongya Zhao
- Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Institute of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
- National Engineering Research Center of Health Care and Medical Devices, Xi'an Jiaotong University Branch, Xi'an 710049, China.
| | - Ruxue Gong
- Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Institute of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
- National Engineering Research Center of Health Care and Medical Devices, Xi'an Jiaotong University Branch, Xi'an 710049, China.
| | - Liang Zheng
- Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Institute of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
- National Engineering Research Center of Health Care and Medical Devices, Xi'an Jiaotong University Branch, Xi'an 710049, China.
| | - Jue Wang
- Key Laboratory of Biomedical Information Engineering of the Ministry of Education, Institute of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
- National Engineering Research Center of Health Care and Medical Devices, Xi'an Jiaotong University Branch, Xi'an 710049, China.
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37
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Eleftheriou CG, Zimmermann JB, Kjeldsen HD, David-Pur M, Hanein Y, Sernagor E. Carbon nanotube electrodes for retinal implants: A study of structural and functional integration over time. Biomaterials 2016; 112:108-121. [PMID: 27760395 PMCID: PMC5123641 DOI: 10.1016/j.biomaterials.2016.10.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 10/08/2016] [Accepted: 10/11/2016] [Indexed: 12/15/2022]
Abstract
The choice of electrode material is of paramount importance in neural prosthetic devices. Electrodes must be biocompatible yet able to sustain repetitive current injections in a highly corrosive environment. We explored the suitability of carbon nanotube (CNT) electrodes to stimulate retinal ganglion cells (RGCs) in a mouse model of outer retinal degeneration. We investigated morphological changes at the bio-hybrid interface and changes in RGC responses to electrical stimulation following prolonged in vitro coupling to CNT electrodes. We observed gradual remodelling of the inner retina to incorporate CNT assemblies. Electrophysiological recordings demonstrate a progressive increase in coupling between RGCs and the CNT electrodes over three days, characterized by a gradual decrease in stimulation thresholds and increase in cellular recruitment. These results provide novel evidence for time-dependent formation of viable bio-hybrids between CNTs and the retina, demonstrating that CNTs are a promising material for inclusion in retinal prosthetic devices.
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Affiliation(s)
- Cyril G Eleftheriou
- Institute of Neuroscience, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, United Kingdom
| | - Jonas B Zimmermann
- Institute of Neuroscience, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, United Kingdom
| | - Henrik D Kjeldsen
- Institute of Neuroscience, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, United Kingdom
| | - Moshe David-Pur
- School of Electrical Engineering, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, 69978, Israel
| | - Yael Hanein
- School of Electrical Engineering, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, 69978, Israel
| | - Evelyne Sernagor
- Institute of Neuroscience, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, United Kingdom.
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Castagnola E, Maggiolini E, Ceseracciu L, Ciarpella F, Zucchini E, De Faveri S, Fadiga L, Ricci D. pHEMA Encapsulated PEDOT-PSS-CNT Microsphere Microelectrodes for Recording Single Unit Activity in the Brain. Front Neurosci 2016; 10:151. [PMID: 27147944 PMCID: PMC4834343 DOI: 10.3389/fnins.2016.00151] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/21/2016] [Indexed: 12/18/2022] Open
Abstract
The long-term reliability of neural interfaces and stability of high-quality recordings are still unsolved issues in neuroscience research. High surface area PEDOT-PSS-CNT composites are able to greatly improve the performance of recording and stimulation for traditional intracortical metal microelectrodes by decreasing their impedance and increasing their charge transfer capability. This enhancement significantly reduces the size of the implantable device though preserving excellent electrical performances. On the other hand, the presence of nanomaterials often rises concerns regarding possible health hazards, especially when considering a clinical application of the devices. For this reason, we decided to explore the problem from a new perspective by designing and testing an innovative device based on nanostructured microspheres grown on a thin tether, integrating PEDOT-PSS-CNT nanocomposites with a soft synthetic permanent biocompatible hydrogel. The pHEMA hydrogel preserves the electrochemical performance and high quality recording ability of PEDOT-PSS-CNT coated devices, reduces the mechanical mismatch between soft brain tissue and stiff devices and also avoids direct contact between the neural tissue and the nanocomposite, by acting as a biocompatible protective barrier against potential nanomaterial detachment. Moreover, the spherical shape of the electrode together with the surface area increase provided by the nanocomposite deposited on it, maximize the electrical contact and may improve recording stability over time. These results have a good potential to contribute to fulfill the grand challenge of obtaining stable neural interfaces for long-term applications.
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Affiliation(s)
- Elisa Castagnola
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
| | - Emma Maggiolini
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
| | - Luca Ceseracciu
- Department of Smart Materials, Istituto Italiano di TecnologiaGenova, Italy
| | | | - Elena Zucchini
- Section of Human Physiology, University of FerraraFerrara, Italy
| | - Sara De Faveri
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
| | - Luciano Fadiga
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
- Section of Human Physiology, University of FerraraFerrara, Italy
| | - Davide Ricci
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di TecnologiaFerrara, Italy
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Jones PD, Stelzle M. Can Nanofluidic Chemical Release Enable Fast, High Resolution Neurotransmitter-Based Neurostimulation? Front Neurosci 2016; 10:138. [PMID: 27065794 PMCID: PMC4815362 DOI: 10.3389/fnins.2016.00138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 03/18/2016] [Indexed: 11/13/2022] Open
Abstract
Artificial chemical stimulation could provide improvements over electrical neurostimulation. Physiological neurotransmission between neurons relies on the nanoscale release and propagation of specific chemical signals to spatially-localized receptors. Current knowledge of nanoscale fluid dynamics and nanofluidic technology allows us to envision artificial mechanisms to achieve fast, high resolution neurotransmitter release. Substantial technological development is required to reach this goal. Nanofluidic technology—rather than microfluidic—will be necessary; this should come as no surprise given the nanofluidic nature of neurotransmission. This perspective reviews the state of the art of high resolution electrical neuroprostheses and their anticipated limitations. Chemical release rates from nanopores are compared to rates achieved at synapses and with iontophoresis. A review of microfluidic technology justifies the analysis that microfluidic control of chemical release would be insufficient. Novel nanofluidic mechanisms are discussed, and we propose that hydrophobic gating may allow control of chemical release suitable for mimicking neurotransmission. The limited understanding of hydrophobic gating in artificial nanopores and the challenges of fabrication and large-scale integration of nanofluidic components are emphasized. Development of suitable nanofluidic technology will require dedicated, long-term efforts over many years.
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Moritz CT, Ruther P, Goering S, Stett A, Ball T, Burgard W, Chudler EH, Rao RPN. New Perspectives on Neuroengineering and Neurotechnologies: NSF-DFG Workshop Report. IEEE Trans Biomed Eng 2016; 63:1354-67. [PMID: 27008657 DOI: 10.1109/tbme.2016.2543662] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
GOAL To identify and overcome barriers to creating new neurotechnologies capable of restoring both motor and sensory function in individuals with neurological conditions. METHODS This report builds upon the outcomes of a joint workshop between the US National Science Foundation and the German Research Foundation on New Perspectives in Neuroengineering and Neurotechnology convened in Arlington, VA, USA, November 13-14, 2014. RESULTS The participants identified key technological challenges for recording and manipulating neural activity, decoding, and interpreting brain data in the presence of plasticity, and early considerations of ethical and social issues pertinent to the adoption of neurotechnologies. CONCLUSIONS The envisaged progress in neuroengineering requires tightly integrated hardware and signal processing efforts, advances in understanding of physiological adaptations to closed-loop interactions with neural devices, and an open dialog with stakeholders and potential end-users of neurotechnology. SIGNIFICANCE The development of new neurotechnologies (e.g., bidirectional brain-computer interfaces) could significantly improve the quality of life of people living with the effects of brain or spinal cord injury, or other neurodegenerative diseases. Focused efforts aimed at overcoming the remaining barriers at the electrode tissue interface, developing implantable hardware with on-board computation, and refining stimulation methods to precisely activate neural tissue will advance both our understanding of brain function and our ability to treat currently intractable disorders of the nervous system.
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Kim YH, Kim GH, Kim AY, Han YH, Chung MA, Jung SD. In vitroextracellular recording and stimulation performance of nanoporous gold-modified multi-electrode arrays. J Neural Eng 2015; 12:066029. [DOI: 10.1088/1741-2560/12/6/066029] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Chung T, Wang JQ, Wang J, Cao B, Li Y, Pang SW. Electrode modifications to lower electrode impedance and improve neural signal recording sensitivity. J Neural Eng 2015; 12:056018. [DOI: 10.1088/1741-2560/12/5/056018] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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