51
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Lu B, Yuk H, Lin S, Jian N, Qu K, Xu J, Zhao X. Pure PEDOT:PSS hydrogels. Nat Commun 2019; 10:1043. [PMID: 30837483 PMCID: PMC6401010 DOI: 10.1038/s41467-019-09003-5] [Citation(s) in RCA: 315] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 02/11/2019] [Indexed: 01/04/2023] Open
Abstract
Hydrogels of conducting polymers, particularly poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), provide a promising electrical interface with biological tissues for sensing and stimulation, owing to their favorable electrical and mechanical properties. While existing methods mostly blend PEDOT:PSS with other compositions such as non-conductive polymers, the blending can compromise resultant hydrogels' mechanical and/or electrical properties. Here, we show that designing interconnected networks of PEDOT:PSS nanofibrils via a simple method can yield high-performance pure PEDOT:PSS hydrogels. The method involves mixing volatile additive dimethyl sulfoxide (DMSO) into aqueous PEDOT:PSS solutions followed by controlled dry-annealing and rehydration. The resultant hydrogels exhibit a set of properties highly desirable for bioelectronic applications, including high electrical conductivity (~20 S cm-1 in PBS, ~40 S cm-1 in deionized water), high stretchability (> 35% strain), low Young's modulus (~2 MPa), superior mechanical, electrical and electrochemical stability, and tunable isotropic/anisotropic swelling in wet physiological environments.
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Affiliation(s)
- Baoyang Lu
- School of Pharmacy, Jiangxi Science and Technology Normal University, 330013, Nanchang, China
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Hyunwoo Yuk
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Shaoting Lin
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Nannan Jian
- School of Pharmacy, Jiangxi Science and Technology Normal University, 330013, Nanchang, China
| | - Kai Qu
- School of Pharmacy, Jiangxi Science and Technology Normal University, 330013, Nanchang, China
| | - Jingkun Xu
- School of Pharmacy, Jiangxi Science and Technology Normal University, 330013, Nanchang, China
- School of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, 266042, Qingdao, China
| | - Xuanhe Zhao
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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52
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Kayser LV, Lipomi DJ. Stretchable Conductive Polymers and Composites Based on PEDOT and PEDOT:PSS. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806133. [PMID: 30600559 PMCID: PMC6401235 DOI: 10.1002/adma.201806133] [Citation(s) in RCA: 345] [Impact Index Per Article: 69.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/23/2018] [Indexed: 04/14/2023]
Abstract
The conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT), and especially its complex with poly(styrene sulfonate) (PEDOT:PSS), is perhaps the most well-known example of an organic conductor. It is highly conductive, largely transmissive to light, processible in water, and highly flexible. Much recent work on this ubiquitous material has been devoted to increasing its deformability beyond flexibility-a characteristic possessed by any material that is sufficiently thin-toward stretchability, a characteristic that requires engineering of the structure at the molecular- or nanoscale. Stretchability is the enabling characteristic of a range of applications envisioned for PEDOT in energy and healthcare, such as wearable, implantable, and large-area electronic devices. High degrees of mechanical deformability allow intimate contact with biological tissues and solution-processable printing techniques (e.g., roll-to-roll printing). PEDOT:PSS, however, is only stretchable up to around 10%. Here, the strategies that have been reported to enhance the stretchability of conductive polymers and composites based on PEDOT and PEDOT:PSS are highlighted. These strategies include blending with plasticizers or polymers, deposition on elastomers, formation of fibers and gels, and the use of intrinsically stretchable scaffolds for the polymerization of PEDOT.
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Affiliation(s)
- Laure V. Kayser
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448, United States,
| | - Darren J. Lipomi
- Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, CA 92093-0448, United States,
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53
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Soft and elastic hydrogel-based microelectronics for localized low-voltage neuromodulation. Nat Biomed Eng 2019; 3:58-68. [DOI: 10.1038/s41551-018-0335-6] [Citation(s) in RCA: 299] [Impact Index Per Article: 59.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 11/27/2018] [Indexed: 12/11/2022]
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54
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Abstract
Hydrogels have emerged as a promising bioelectronic interfacing material. This review discusses the fundamentals and recent advances in hydrogel bioelectronics.
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Affiliation(s)
- Hyunwoo Yuk
- Department of Mechanical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
| | - Baoyang Lu
- Department of Mechanical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
- School of Pharmacy
| | - Xuanhe Zhao
- Department of Mechanical Engineering
- Massachusetts Institute of Technology
- Cambridge
- USA
- Department of Civil and Environmental Engineering
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55
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Goding J, Vallejo-Giraldo C, Syed O, Green R. Considerations for hydrogel applications to neural bioelectronics. J Mater Chem B 2019; 7:1625-1636. [DOI: 10.1039/c8tb02763c] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hydrogels have garnered interest as materials in bioelectronics due to the capacity to tailor their properties. Appropriate selection and design of hydrogel systems for this application requires an understanding of the physical, chemical and biological properties as well as their structure–property relationships.
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Affiliation(s)
- Josef Goding
- Department of Bioengineering
- Imperial College London
- London SW72AS
- UK
| | | | - Omaer Syed
- Department of Bioengineering
- Imperial College London
- London SW72AS
- UK
| | - Rylie Green
- Department of Bioengineering
- Imperial College London
- London SW72AS
- UK
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56
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Yamazawa Y, Kato H, Nakaji-Hirabayashi T, Yoshikawa C, Kitano H, Ohno K, Saruwatari Y, Matsuoka K. Bioinactive semi-interpenetrating network gel layers: zwitterionic polymer chains incorporated in a cross-linked polymer brush. J Mater Chem B 2019. [DOI: 10.1039/c8tb03228a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A thin gel layer with thermo-responsive polymer brushes and semi-interpenetrating PCMB exhibited the switching of bio-inert properties depending on temperature.
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Affiliation(s)
- Yuka Yamazawa
- Graduate School of Science and Engineering
- University of Toyama
- Toyama 930-8555
- Japan
| | - Hibiki Kato
- Graduate School of Science and Engineering
- University of Toyama
- Toyama 930-8555
- Japan
| | - Tadashi Nakaji-Hirabayashi
- Graduate School of Science and Engineering
- University of Toyama
- Toyama 930-8555
- Japan
- Graduate School of Innovative Life Sciences
| | - Chiaki Yoshikawa
- International Centre for Materials Nanoarchitectonics
- National Institute of Material Science
- Ibaraki 305-0047
- Japan
| | - Hiromi Kitano
- Graduate School of Science and Engineering
- University of Toyama
- Toyama 930-8555
- Japan
- Graduate School of Innovative Life Sciences
| | - Kohji Ohno
- Institute for Chemical Research
- Kyoto University
- Kyoto 611-0011
- Japan
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57
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Ferlauto L, D'Angelo AN, Vagni P, Airaghi Leccardi MJI, Mor FM, Cuttaz EA, Heuschkel MO, Stoppini L, Ghezzi D. Development and Characterization of PEDOT:PSS/Alginate Soft Microelectrodes for Application in Neuroprosthetics. Front Neurosci 2018; 12:648. [PMID: 30283296 PMCID: PMC6156361 DOI: 10.3389/fnins.2018.00648] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 08/30/2018] [Indexed: 01/28/2023] Open
Abstract
Reducing the mechanical mismatch between the stiffness of a neural implant and the softness of the neural tissue is still an open challenge in neuroprosthetics. The emergence of conductive hydrogels in the last few years has considerably widened the spectrum of possibilities to tackle this issue. Nevertheless, despite the advancements in this field, further improvements in the fabrication of conductive hydrogel-based electrodes are still required. In this work, we report the fabrication of a conductive hydrogel-based microelectrode array for neural recording using a hybrid material composed of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), and alginate. The mechanical properties of the conductive hydrogel have been investigated using imaging techniques, while the electrode arrays have been electrochemically characterized at each fabrication step, and successfully validated both in vitro and in vivo. The presence of the conductive hydrogel, selectively electrodeposited onto the platinum microelectrodes, allowed achieving superior electrochemical characteristics, leading to a lower electrical noise during recordings. These findings represent an advancement in the design of soft conductive electrodes for neuroprosthetic applications.
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Affiliation(s)
- Laura Ferlauto
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Antonio Nunzio D'Angelo
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Paola Vagni
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Marta Jole Ildelfonsa Airaghi Leccardi
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Flavio Maurizio Mor
- Tissue Engineering Laboratory, HEPIA, University of Applied Sciences and Arts Western Switzerland (HES-SO), Geneva, Switzerland
| | - Estelle Annick Cuttaz
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Marc Olivier Heuschkel
- Tissue Engineering Laboratory, HEPIA, University of Applied Sciences and Arts Western Switzerland (HES-SO), Geneva, Switzerland
| | - Luc Stoppini
- Tissue Engineering Laboratory, HEPIA, University of Applied Sciences and Arts Western Switzerland (HES-SO), Geneva, Switzerland
| | - Diego Ghezzi
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
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58
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Hydrogel Scaffolds: Towards Restitution of Ischemic Stroke-Injured Brain. Transl Stroke Res 2018; 10:1-18. [DOI: 10.1007/s12975-018-0655-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/17/2018] [Accepted: 08/19/2018] [Indexed: 12/27/2022]
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59
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Feron K, Lim R, Sherwood C, Keynes A, Brichta A, Dastoor PC. Organic Bioelectronics: Materials and Biocompatibility. Int J Mol Sci 2018; 19:E2382. [PMID: 30104515 PMCID: PMC6121695 DOI: 10.3390/ijms19082382] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/08/2018] [Accepted: 08/10/2018] [Indexed: 01/06/2023] Open
Abstract
Organic electronic materials have been considered for a wide-range of technological applications. More recently these organic (semi)conductors (encompassing both conducting and semi-conducting organic electronic materials) have received increasing attention as materials for bioelectronic applications. Biological tissues typically comprise soft, elastic, carbon-based macromolecules and polymers, and communication in these biological systems is usually mediated via mixed electronic and ionic conduction. In contrast to hard inorganic semiconductors, whose primary charge carriers are electrons and holes, organic (semi)conductors uniquely match the mechanical and conduction properties of biotic tissue. Here, we review the biocompatibility of organic electronic materials and their implementation in bioelectronic applications.
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Affiliation(s)
- Krishna Feron
- Centre for Organic Electronics, University of Newcastle, Callaghan, Newcastle, NSW 2308, Australia.
| | - Rebecca Lim
- Centre for Brain and Mental Health Research, University of Newcastle, Callaghan, Newcastle, NSW 2308, Australia.
| | - Connor Sherwood
- Centre for Organic Electronics, University of Newcastle, Callaghan, Newcastle, NSW 2308, Australia.
- Centre for Brain and Mental Health Research, University of Newcastle, Callaghan, Newcastle, NSW 2308, Australia.
| | - Angela Keynes
- Centre for Brain and Mental Health Research, University of Newcastle, Callaghan, Newcastle, NSW 2308, Australia.
| | - Alan Brichta
- Centre for Brain and Mental Health Research, University of Newcastle, Callaghan, Newcastle, NSW 2308, Australia.
| | - Paul C Dastoor
- Centre for Organic Electronics, University of Newcastle, Callaghan, Newcastle, NSW 2308, Australia.
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60
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Mechanically tunable conductive interpenetrating network hydrogels that mimic the elastic moduli of biological tissue. Nat Commun 2018; 9:2740. [PMID: 30013027 PMCID: PMC6048132 DOI: 10.1038/s41467-018-05222-4] [Citation(s) in RCA: 218] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/21/2018] [Indexed: 12/27/2022] Open
Abstract
Conductive and stretchable materials that match the elastic moduli of biological tissue (0.5–500 kPa) are desired for enhanced interfacial and mechanical stability. Compared with inorganic and dry polymeric conductors, hydrogels made with conducting polymers are promising soft electrode materials due to their high water content. Nevertheless, most conducting polymer-based hydrogels sacrifice electronic performance to obtain useful mechanical properties. Here we report a method that overcomes this limitation using two interpenetrating hydrogel networks, one of which is formed by the gelation of the conducting polymer PEDOT:PSS. Due to the connectivity of the PEDOT:PSS network, conductivities up to 23 S m−1 are achieved, a record for stretchable PEDOT:PSS-based hydrogels. Meanwhile, the low concentration of PEDOT:PSS enables orthogonal control over the composite mechanical properties using a secondary polymer network. We demonstrate tunability of the elastic modulus over three biologically relevant orders of magnitude without compromising stretchability ( > 100%) or conductivity ( > 10 S m−1). Conductive and stretchable materials that match the elastic moduli of biological tissue are desired for enhanced interfacial and mechanical stability. Here the authors show a method for fabricating highly conductive hydrogels comprising two interpenetrating networks.
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61
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Gilmour A, Goding J, Robles UA, Staples N, Byrnes-Preston P, Morley J, Lovell NH, Chew DJ, Green R. Stimulation of peripheral nerves using conductive hydrogel electrodes. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:5475-5478. [PMID: 30441576 DOI: 10.1109/embc.2018.8513628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nerve block via electrical stimulation of nerves requires a device capable of transferring large amounts of charge across the neural interface on chronic time scales. Current metal electrode designs are limited in their ability to safely and effectively deliver this charge in a stable manner. Conductive hydrogel (CH) coatings are a promising alternative to metal electrodes for neural interfacing devices. This study assessed the performance of CH electrodes compared to platinum-iridium (PtIr) electrodes in commercial nerve cuff devices in both the in vitro and acute in vivo environments. CH electrodes were found to have higher charge storage capacities and lower impedances compared to bare PtIr electrodes. Application of CH coatings also resulted in a three-fold increase in in vivo charge injection limit. These significant improvements in electrochemical properties will allow for the design of smaller and safer stimulating devices for nerve block applications.
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62
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Wang S, Guo G, Lu X, Ji S, Tan G, Gao L. Facile Soaking Strategy Toward Simultaneously Enhanced Conductivity and Toughness of Self-Healing Composite Hydrogels Through Constructing Multiple Noncovalent Interactions. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19133-19142. [PMID: 29756768 DOI: 10.1021/acsami.8b04999] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Tough and stretchable conductive hydrogels are desirable for the emerging field of wearable and implanted electronics. Unfortunately, most existing conductive hydrogels have low mechanical strength. Current strategies to enhance mechanical properties include employing tough host gel matrices or introducing specific interaction between conductive polymer and host gel matrices. However, these strategies often involve additional complicated processes. Here, a simple yet effective soaking treatment is employed to concurrently enhance mechanical and conductive properties, both of which can be facilely tailored by controlling the soaking duration. The significant improvements are correlated with co-occurring mechanism of deswelling and multiple noncovalent interactions. The resulting optimal sample exhibits attractive combination of high water content (75 wt %), high tensile stress (∼2.5 MPa), large elongation (>600%), reasonable conductivity (∼25 mS/cm), and fast self-healing property with the aid of hot water. The potential application of gel as a strain sensor is demonstrated. The applicability of this method is not limited to conductive hydrogels alone but can also be extended to strengthen other functional hydrogels with weak mechanical properties.
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Affiliation(s)
- Shuting Wang
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Guoqiang Guo
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Xiaoxuan Lu
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Shaomin Ji
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Guoxin Tan
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
| | - Liang Gao
- School of Chemical Engineering and Light Industry , Guangdong University of Technology , Guangzhou 510006 , China
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63
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Lim KS, Levato R, Costa PF, Castilho MD, Alcala-Orozco CR, van Dorenmalen KMA, Melchels FPW, Gawlitta D, Hooper GJ, Malda J, Woodfield TBF. Bio-resin for high resolution lithography-based biofabrication of complex cell-laden constructs. Biofabrication 2018; 10:034101. [DOI: 10.1088/1758-5090/aac00c] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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64
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Staples NA, Goding JA, Gilmour AD, Aristovich KY, Byrnes-Preston P, Holder DS, Morley JW, Lovell NH, Chew DJ, Green RA. Conductive Hydrogel Electrodes for Delivery of Long-Term High Frequency Pulses. Front Neurosci 2018; 11:748. [PMID: 29375292 PMCID: PMC5768631 DOI: 10.3389/fnins.2017.00748] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/22/2017] [Indexed: 11/17/2022] Open
Abstract
Nerve block waveforms require the passage of large amounts of electrical energy at the neural interface for extended periods of time. It is desirable that such waveforms be applied chronically, consistent with the treatment of protracted immune conditions, however current metal electrode technologies are limited in their capacity to safely deliver ongoing stable blocking waveforms. Conductive hydrogel (CH) electrode coatings have been shown to improve the performance of conventional bionic devices, which use considerably lower amounts of energy than conventional metal electrodes to replace or augment sensory neuron function. In this study the application of CH materials was explored, using both a commercially available platinum iridium (PtIr) cuff electrode array and a novel low-cost stainless steel (SS) electrode array. The CH was able to significantly increase the electrochemical performance of both array types. The SS electrode coated with the CH was shown to be stable under continuous delivery of 2 mA square pulse waveforms at 40,000 Hz for 42 days. CH coatings have been shown as a beneficial electrode material compatible with long-term delivery of high current, high energy waveforms.
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Affiliation(s)
- Naomi A Staples
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Josef A Goding
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia.,Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Aaron D Gilmour
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Kirill Y Aristovich
- Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Phillip Byrnes-Preston
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - David S Holder
- Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - John W Morley
- School of Medical Science, University of New South Wales, Sydney, NSW, Australia.,School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Nigel H Lovell
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | | | - Rylie A Green
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia.,Department of Bioengineering, Imperial College London, London, United Kingdom
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65
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Molina BG, Cianga L, Bendrea AD, Cianga I, del Valle LJ, Estrany F, Alemán C, Armelin E. Amphiphilic polypyrrole-poly(Schiff base) copolymers with poly(ethylene glycol) side chains: synthesis, properties and applications. Polym Chem 2018. [DOI: 10.1039/c8py00762d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
New amphiphilic poly(ethylene glycol) (PEG)-grafted random intrinsically conducting copolymers which combine three different functionalities have been engineered, prepared and characterized.
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Affiliation(s)
- Brenda G. Molina
- Departament d'Enginyeria Química
- EEBE
- Universitat Politècnica de Catalunya
- Barcelona
- Spain
| | - Luminita Cianga
- “Petru Poni” Institute of Macromolecular Chemistry
- Iasi
- Romania
| | | | - Ioan Cianga
- “Petru Poni” Institute of Macromolecular Chemistry
- Iasi
- Romania
| | - Luis J. del Valle
- Departament d'Enginyeria Química
- EEBE
- Universitat Politècnica de Catalunya
- Barcelona
- Spain
| | - Francesc Estrany
- Departament d'Enginyeria Química
- EEBE
- Universitat Politècnica de Catalunya
- Barcelona
- Spain
| | - Carlos Alemán
- Departament d'Enginyeria Química
- EEBE
- Universitat Politècnica de Catalunya
- Barcelona
- Spain
| | - Elaine Armelin
- Departament d'Enginyeria Química
- EEBE
- Universitat Politècnica de Catalunya
- Barcelona
- Spain
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66
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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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67
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Marcus M, Baranes K, Park M, Choi IS, Kang K, Shefi O. Interactions of Neurons with Physical Environments. Adv Healthc Mater 2017. [PMID: 28640544 DOI: 10.1002/adhm.201700267] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nerve growth strongly relies on multiple chemical and physical signals throughout development and regeneration. Currently, a cure for injured neuronal tissue is an unmet need. Recent advances in fabrication technologies and materials led to the development of synthetic interfaces for neurons. Such engineered platforms that come in 2D and 3D forms can mimic the native extracellular environment and create a deeper understanding of neuronal growth mechanisms, and ultimately advance the development of potential therapies for neuronal regeneration. This progress report aims to present a comprehensive discussion of this field, focusing on physical feature design and fabrication with additional information about considerations of chemical modifications. We review studies of platforms generated with a range of topographies, from micro-scale features down to topographical elements at the nanoscale that demonstrate effective interactions with neuronal cells. Fabrication methods are discussed as well as their biological outcomes. This report highlights the interplay between neuronal systems and the important roles played by topography on neuronal differentiation, outgrowth, and development. The influence of substrate structures on different neuronal cells and parameters including cell fate, outgrowth, intracellular remodeling, gene expression and activity is discussed. Matching these effects to specific needs may lead to the emergence of clinical solutions for patients suffering from neuronal injuries or brain-machine interface (BMI) applications.
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Affiliation(s)
- Michal Marcus
- Faculty of Engineering and Bar-Ilan Institute for Nanotechnology and Advanced Materials; Bar-Ilan University; Ramat-Gan 5290002 Israel
| | - Koby Baranes
- Faculty of Engineering and Bar-Ilan Institute for Nanotechnology and Advanced Materials; Bar-Ilan University; Ramat-Gan 5290002 Israel
| | - Matthew Park
- Center for Cell-Encapsulation Research; Department of Chemistry; KAIST; Daejeon 34141 Korea
| | - Insung S. Choi
- Center for Cell-Encapsulation Research; Department of Chemistry; KAIST; Daejeon 34141 Korea
| | - Kyungtae Kang
- Department of Applied Chemistry; Kyung Hee University; Yongin Gyeonggi 17104 Korea
| | - Orit Shefi
- Faculty of Engineering and Bar-Ilan Institute for Nanotechnology and Advanced Materials; Bar-Ilan University; Ramat-Gan 5290002 Israel
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Kleber C, Bruns M, Lienkamp K, Rühe J, Asplund M. An interpenetrating, microstructurable and covalently attached conducting polymer hydrogel for neural interfaces. Acta Biomater 2017; 58:365-375. [PMID: 28578108 DOI: 10.1016/j.actbio.2017.05.056] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 05/19/2017] [Accepted: 05/30/2017] [Indexed: 01/25/2023]
Abstract
This study presents a new conducting polymer hydrogel (CPH) system, consisting of the synthetic hydrogel P(DMAA-co-5%MABP-co-2,5%SSNa) and the conducting polymer (CP) poly(3,4-ethylenedioxythiophene) (PEDOT), intended as coating material for neural interfaces. The composite material can be covalently attached to the surface electrode, can be patterned by a photolithographic process to influence selected electrode sites only and forms an interpenetrating network. The hybrid material was characterized using cyclic voltammetry (CV), impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS), which confirmed a homogeneous distribution of PEDOT throughout all CPH layers. The CPH exhibited a 2,5 times higher charge storage capacity (CSC) and a reduced impedance when compared to the bare hydrogel. Electrochemical stability was proven over at least 1000 redox cycles. Non-toxicity was confirmed using an elution toxicity test together with a neuroblastoma cell-line. The described material shows great promise for surface modification of neural probes making it possible to combine the beneficial properties of the hydrogel with the excellent electronic properties necessary for high quality neural microelectrodes. STATEMENT OF SIGNIFICANCE Conductive polymer hydrogels have emerged as a promising new class of materials to functionalize electrode surfaces for enhanced neural interfaces and drug delivery. Common weaknesses of such systems are delamination from the connection surface, and the lack of suitable patterning methods for confining the gel to the selected electrode site. Various studies have reported on conductive polymer hydrogels addressing one of these challenges. In this study we present a new composite material which offers, for the first time, the unique combination of properties: it can be covalently attached to the substrate, forms an interpenetrating network, shows excellent electrical properties and can be patterned via UV-irradiation through a structured mask.
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Affiliation(s)
- Carolin Kleber
- BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany.
| | - Michael Bruns
- Institute for Applied Materials (IAM) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Karen Lienkamp
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany
| | - Jürgen Rühe
- BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany
| | - Maria Asplund
- BrainLinks-BrainTools Center, University of Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Germany
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