51
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A mechanically strong conductive hydrogel reinforced by diaminotriazine hydrogen bonding. CHINESE JOURNAL OF POLYMER SCIENCE 2017. [DOI: 10.1007/s10118-017-1960-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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52
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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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53
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Goding J, Gilmour A, Martens P, Poole-Warren L, Green R. Interpenetrating Conducting Hydrogel Materials for Neural Interfacing Electrodes. Adv Healthc Mater 2017; 6. [PMID: 28198591 DOI: 10.1002/adhm.201601177] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/09/2017] [Indexed: 01/05/2023]
Abstract
Conducting hydrogels (CHs) are an emerging technology in the field of medical electrodes and brain-machine interfaces. The greatest challenge to the fabrication of CH electrodes is the hybridization of dissimilar polymers (conductive polymer and hydrogel) to ensure the formation of interpenetrating polymer networks (IPN) required to achieve both soft and electroactive materials. A new hydrogel system is developed that enables tailored placement of covalently immobilized dopant groups within the hydrogel matrix. The role of immobilized dopant in the formation of CH is investigated through covalent linking of sulfonate doping groups to poly(vinyl alcohol) (PVA) macromers. These groups control the electrochemical growth of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and subsequent material properties. The effect of dopant density and interdopant spacing on the physical, electrochemical, and mechanical properties of the resultant CHs is examined. Cytocompatible PVA hydrogels with PEDOT penetration throughout the depth of the electrode are produced. Interdopant spacing is found to be the key factor in the formation of IPNs, with smaller interdopant spacing producing CH electrodes with greater charge storage capacity and lower impedance due to increased PEDOT growth throughout the network. This approach facilitates tailorable, high-performance CH electrodes for next generation, low impedance neuroprosthetic devices.
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Affiliation(s)
- Josef Goding
- Graduate School of Biomedical Engineering; University of New South Wales; Sydney NSW 2052 Australia
| | - Aaron Gilmour
- Graduate School of Biomedical Engineering; University of New South Wales; Sydney NSW 2052 Australia
| | - Penny Martens
- Graduate School of Biomedical Engineering; University of New South Wales; Sydney NSW 2052 Australia
| | - Laura Poole-Warren
- Graduate School of Biomedical Engineering; University of New South Wales; Sydney NSW 2052 Australia
| | - Rylie Green
- Graduate School of Biomedical Engineering; University of New South Wales; Sydney NSW 2052 Australia
- Department of Bioengineering; Imperial College London; London SW72BP UK
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54
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Conductive nanogel-interfaced neural microelectrode arrays with electrically controlled in-situ delivery of manganese ions enabling high-resolution MEMRI for synchronous neural tracing with deep brain stimulation. Biomaterials 2017; 122:141-153. [DOI: 10.1016/j.biomaterials.2017.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/23/2016] [Accepted: 01/10/2017] [Indexed: 12/22/2022]
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55
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Hassarati RT, Foster LJR, Green RA. Influence of Biphasic Stimulation on Olfactory Ensheathing Cells for Neuroprosthetic Devices. Front Neurosci 2016; 10:432. [PMID: 27757072 PMCID: PMC5048075 DOI: 10.3389/fnins.2016.00432] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 09/06/2016] [Indexed: 12/19/2022] Open
Abstract
The recent success of olfactory ensheathing cell (OEC) assisted regeneration of injured spinal cord has seen a rising interest in the use of these cells in tissue-engineered systems. Previously shown to support neural cell growth through glial scar tissue, OECs have the potential to assist neural network formation in living electrode systems to produce superior neuroprosthetic electrode surfaces. The following study sought to understand the influence of biphasic electrical stimulation (ES), inherent to bionic devices, on cell survival and function, with respect to conventional metallic and developmental conductive hydrogel (CH) coated electrodes. The CH utilized in this study was a biosynthetic hydrogel consisting of methacrylated poly(vinyl-alcohol) (PVA), heparin and gelatin through which poly(3,4-ethylenedioxythiophene) (PEDOT) was electropolymerised. OECs cultured on Pt and CH surfaces were subjected to biphasic ES. Image-based cytometry yielded little significant difference between the viability and cell cycle of OECs cultured on the stimulated and passive samples. The significantly lower voltages measured across the CH electrodes (147 ± 3 mV) compared to the Pt (317 ± 5 mV), had shown to influence a higher percentage of viable cells on CH (91–93%) compared to Pt (78–81%). To determine the functionality of these cells following electrical stimulation, OECs co-cultured with PC12 cells were found to support neural cell differentiation (an indirect measure of neurotrophic factor production) following ES.
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Affiliation(s)
- Rachelle T Hassarati
- Graduate School of Biomedical Engineering, University of New South Wales Australia Sydney, NSW, Australia
| | - L John R Foster
- Bio/Polymers Research Group, School of Biotechnology and Biomolecular Sciences, University of New South Wales Australia Sydney, NSW, Australia
| | - Rylie A Green
- Graduate School of Biomedical Engineering, University of New South Wales Australia Sydney, NSW, Australia
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56
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Bhagwat N, Murray RE, Shah SI, Kiick KL, Martin DC. Biofunctionalization of PEDOT films with laminin-derived peptides. Acta Biomater 2016; 41:235-46. [PMID: 27181880 DOI: 10.1016/j.actbio.2016.05.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 04/24/2016] [Accepted: 05/11/2016] [Indexed: 01/06/2023]
Abstract
UNLABELLED Poly(3,4-ethylenedioxythiophenes) (PEDOT) have been extensively explored as materials for biomedical implants such as biosensors, tissue engineering scaffolds and microelectronic devices. Considerable effort has been made to incorporate biologically active molecules into the conducting polymer films in order to improve their long term performance at the soft tissue interface of devices, and the development of functionalized conducting polymers that can be modified with biomolecules would offer important options for device improvement. Here we report surface modification, via straightforward protocols, of carboxylic-acid-functional PEDOT copolymer films with the nonapeptide, CDPGYIGSR, derived from the basement membrane protein laminin. Evaluation of the modified surfaces via XPS and toluidine blue O assay confirmed the presence of the peptide on the surface and electrochemical analysis demonstrated unaltered properties of the peptide-modified films. The efficacy of the peptide, along with the impact of a spacer molecule, for cell adhesion and differentiation was tested in cell culture assays employing the rat pheochromocytoma (PC12) cell line. Peptide-modified films comprising the longest poly(ethylene glycol) (PEG) spacer used in this study, a PEG with ten ethylene glycol repeats, demonstrated the best attachment and neurite outgrowth compared to films with peptides alone or those with a PEG spacer comprising three ethylene glycol units. The films with PEG10-CDPGYISGR covalently modified to the surface demonstrated 11.5% neurite expression with a mean neurite length of 90μm. This peptide immobilization technique provides an effective approach to biofunctionalize conducting polymer films. STATEMENT OF SIGNIFICANCE For enhanced diagnosis and treatment, electronic devices that interface with living tissue with minimum shortcomings are critical. Towards these ends, conducting polymers have proven to be excellent materials for electrode-tissue interface for a variety of biomedical devices ranging from deep brain stimulators, cochlear implants, and microfabricated cortical electrodes. To improve the electrode-tissue interface, one strategy utilized by many researchers is incorporating relevant biological molecules within or on the conducting polymer thin films to provide a surface for cell attachment and/or provide biological cues for cell growth. The present study provides a facile means for generating PEDOT films grafted with a laminin peptide with or without a spacer molecule for enhanced cell attachment and neurite extension.
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Affiliation(s)
- Nandita Bhagwat
- Department of Materials Science and Engineering, University of Delaware, 19716, USA
| | - Roy E Murray
- Department of Physics and Astronomy, University of Delaware, 19716, USA
| | - S Ismat Shah
- Department of Materials Science and Engineering, University of Delaware, 19716, USA; Department of Physics and Astronomy, University of Delaware, 19716, USA
| | - Kristi L Kiick
- Department of Materials Science and Engineering, University of Delaware, 19716, USA.
| | - David C Martin
- Department of Materials Science and Engineering, University of Delaware, 19716, USA.
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57
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Xu C, Yepez G, Wei Z, Liu F, Bugarin A, Hong Y. Synthesis and characterization of conductive, biodegradable, elastomeric polyurethanes for biomedical applications. J Biomed Mater Res A 2016; 104:2305-14. [PMID: 27124702 PMCID: PMC10947274 DOI: 10.1002/jbm.a.35765] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 04/23/2016] [Accepted: 04/26/2016] [Indexed: 11/11/2022]
Abstract
Biodegradable conductive polymers are currently of significant interest in tissue repair and regeneration, drug delivery, and bioelectronics. However, biodegradable materials exhibiting both conductive and elastic properties have rarely been reported to date. To that end, an electrically conductive polyurethane (CPU) was synthesized from polycaprolactone diol, hexadiisocyanate, and aniline trimer and subsequently doped with (1S)-(+)-10-camphorsulfonic acid (CSA). All CPU films showed good elasticity within a 30% strain range. The electrical conductivity of the CPU films, as enhanced with increasing amounts of CSA, ranged from 2.7 ± 0.9 × 10(-10) to 4.4 ± 0.6 × 10(-7) S/cm in a dry state and 4.2 ± 0.5 × 10(-8) to 7.3 ± 1.5 × 10(-5) S/cm in a wet state. The redox peaks of a CPU1.5 film (molar ratio CSA:aniline trimer = 1.5:1) in the cyclic voltammogram confirmed the desired good electroactivity. The doped CPU film exhibited good electrical stability (87% of initial conductivity after 150 hours charge) as measured in a cell culture medium. The degradation rates of CPU films increased with increasing CSA content in both phosphate-buffered solution (PBS) and lipase/PBS solutions. After 7 days of enzymatic degradation, the conductivity of all CSA-doped CPU films had decreased to that of the undoped CPU film. Mouse 3T3 fibroblasts proliferated and spread on all CPU films. This developed biodegradable CPU with good elasticity, electrical stability, and biocompatibility may find potential applications in tissue engineering, smart drug release, and electronics. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2305-2314, 2016.
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Affiliation(s)
- Cancan Xu
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
- Joint Biomedical Engineering Program, University of Texas Southwestern Medical Center, Dallas, TX 75093, USA
| | - Gerardo Yepez
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, USA
| | - Zi Wei
- Department of Material Science and Engineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Fuqiang Liu
- Department of Material Science and Engineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Alejandro Bugarin
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, USA
| | - Yi Hong
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
- Joint Biomedical Engineering Program, University of Texas Southwestern Medical Center, Dallas, TX 75093, USA
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58
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Meijs S, Alcaide M, Sørensen C, McDonald M, Sørensen S, Rechendorff K, Gerhardt A, Nesladek M, Rijkhoff NJM, Pennisi CP. Biofouling resistance of boron-doped diamond neural stimulation electrodes is superior to titanium nitride electrodesin vivo. J Neural Eng 2016; 13:056011. [DOI: 10.1088/1741-2560/13/5/056011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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59
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Patton AJ, Poole-Warren LA, Green RA. Mechanisms for Imparting Conductivity to Nonconductive Polymeric Biomaterials. Macromol Biosci 2016; 16:1103-21. [DOI: 10.1002/mabi.201600057] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/31/2016] [Indexed: 11/08/2022]
Affiliation(s)
| | | | - Rylie A. Green
- Graduate School of Biomedical Engineering; University of New South Wales
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60
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Fang L, Zhao L, Liang X, Xiao H, Qian L. Effects of oxidant and dopants on the properties of cellulose/PPy conductive composite hydrogels. J Appl Polym Sci 2016. [DOI: 10.1002/app.43759] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Liangjing Fang
- School of Light Industry and Engineering, State Key Laboratory of Pulp and Paper Engineering; South China University of Technology; Guangzhou 510640 China
| | - Lihong Zhao
- School of Light Industry and Engineering, State Key Laboratory of Pulp and Paper Engineering; South China University of Technology; Guangzhou 510640 China
| | - Xiangtao Liang
- School of Light Industry and Engineering, State Key Laboratory of Pulp and Paper Engineering; South China University of Technology; Guangzhou 510640 China
| | - Huining Xiao
- Department of Chemical Engineering; University of New Brunswick; Fredericton E3B 5A3 New Brunswick Canada
| | - Liying Qian
- School of Light Industry and Engineering, State Key Laboratory of Pulp and Paper Engineering; South China University of Technology; Guangzhou 510640 China
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61
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Alves-Sampaio A, García-Rama C, Collazos-Castro JE. Biofunctionalized PEDOT-coated microfibers for the treatment of spinal cord injury. Biomaterials 2016; 89:98-113. [DOI: 10.1016/j.biomaterials.2016.02.037] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/11/2016] [Accepted: 02/23/2016] [Indexed: 12/26/2022]
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62
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Recco MS, Floriano AC, Tada DB, Lemes AP, Lang R, Cristovan FH. Poly(3-hydroxybutyrate-co-valerate)/poly(3-thiophene ethyl acetate) blends as a electroactive biomaterial substrate for tissue engineering application. RSC Adv 2016. [DOI: 10.1039/c5ra26747a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Polyblend films based on poly(3-hydroxybutirate-co-valerate) and poly(3-thiophene ethyl acetate) – PHBV/PTAcEt showed low cytotoxicity, good adhesion and mammalian cell proliferation. The physical–chemical properties were explored.
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Affiliation(s)
- M. S. Recco
- Institute of Science and Technology
- Universidade Federal de São Paulo – UNIFESP
- São José dos Campos
- Brazil
| | - A. C. Floriano
- Institute of Science and Technology
- Universidade Federal de São Paulo – UNIFESP
- São José dos Campos
- Brazil
| | - D. B. Tada
- Institute of Science and Technology
- Universidade Federal de São Paulo – UNIFESP
- São José dos Campos
- Brazil
| | - A. P. Lemes
- Institute of Science and Technology
- Universidade Federal de São Paulo – UNIFESP
- São José dos Campos
- Brazil
| | - R. Lang
- Institute of Science and Technology
- Universidade Federal de São Paulo – UNIFESP
- São José dos Campos
- Brazil
| | - F. H. Cristovan
- Institute of Science and Technology
- Universidade Federal de São Paulo – UNIFESP
- São José dos Campos
- Brazil
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63
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Roberts JJ, Farrugia BL, Green RA, Rnjak-Kovacina J, Martens PJ. In situ formation of poly(vinyl alcohol)-heparin hydrogels for mild encapsulation and prolonged release of basic fibroblast growth factor and vascular endothelial growth factor. J Tissue Eng 2016; 7:2041731416677132. [PMID: 27895888 PMCID: PMC5117248 DOI: 10.1177/2041731416677132] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 10/11/2016] [Indexed: 12/12/2022] Open
Abstract
Heparin-based hydrogels are attractive for controlled growth factor delivery, due to the native ability of heparin to bind and stabilize growth factors. Basic fibroblast growth factor and vascular endothelial growth factor are heparin-binding growth factors that synergistically enhance angiogenesis. Mild, in situ encapsulation of both basic fibroblast growth factor and vascular endothelial growth factor and subsequent bioactive dual release has not been demonstrated from heparin-crosslinked hydrogels, and the combined long-term delivery of both growth factors from biomaterials is still a major challenge. Both basic fibroblast growth factor and vascular endothelial growth factor were encapsulated in poly(vinyl alcohol)-heparin hydrogels and demonstrated controlled release. A model cell line, BaF32, was used to show bioactivity of heparin and basic fibroblast growth factor released from the gels over multiple days. Released basic fibroblast growth factor promoted higher human umbilical vein endothelial cell outgrowth over 24 h and proliferation for 3 days than the poly(vinyl alcohol)-heparin hydrogels alone. The release of vascular endothelial growth factor from poly(vinyl alcohol)-heparin hydrogels promoted human umbilical vein endothelial cell outgrowth but not significant proliferation. Dual-growth factor release of basic fibroblast growth factor and vascular endothelial growth factor from poly(vinyl alcohol)-heparin hydrogels resulted in a synergistic effect with significantly higher human umbilical vein endothelial cell outgrowth compared to basic fibroblast growth factor or vascular endothelial growth factor alone. Poly(vinyl alcohol)-heparin hydrogels allowed bioactive growth factor encapsulation and provided controlled release of multiple growth factors which is beneficial toward tissue regeneration applications.
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Affiliation(s)
| | | | | | | | - Penny J Martens
- Graduate School of Biomedical Engineering, UNSW Australia, Sydney, NSW, Australia
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64
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Green R, Abidian MR. Conducting Polymers for Neural Prosthetic and Neural Interface Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:7620-37. [PMID: 26414302 PMCID: PMC4681501 DOI: 10.1002/adma.201501810] [Citation(s) in RCA: 193] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 06/11/2015] [Indexed: 05/20/2023]
Abstract
Neural-interfacing devices are an artificial mechanism for restoring or supplementing the function of the nervous system, lost as a result of injury or disease. Conducting polymers (CPs) are gaining significant attention due to their capacity to meet the performance criteria of a number of neuronal therapies including recording and stimulating neural activity, the regeneration of neural tissue and the delivery of bioactive molecules for mediating device-tissue interactions. CPs form a flexible platform technology that enables the development of tailored materials for a range of neuronal diagnostic and treatment therapies. In this review, the application of CPs for neural prostheses and other neural interfacing devices is discussed, with a specific focus on neural recording, neural stimulation, neural regeneration, and therapeutic drug delivery.
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Affiliation(s)
- Rylie Green
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Mohammad Reza Abidian
- Biomedical Engineering Department, Materials Science & Engineering Department, Chemical Engineering Department, Materials Research Institute, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 (USA)
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65
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Hassarati RT, Marcal H, John L, Foster R, Green RA. Biofunctionalization of conductive hydrogel coatings to support olfactory ensheathing cells at implantable electrode interfaces. J Biomed Mater Res B Appl Biomater 2015; 104:712-22. [PMID: 26248597 DOI: 10.1002/jbm.b.33497] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 07/09/2015] [Accepted: 07/18/2015] [Indexed: 11/06/2022]
Abstract
Mechanical discrepancies between conventional platinum (Pt) electrodes and neural tissue often result in scar tissue encapsulation of implanted neural recording and stimulating devices. Olfactory ensheathing cells (OECs) are a supportive glial cell in the olfactory nervous system which can transition through glial scar tissue while supporting the outgrowth of neural processes. It has been proposed that this function can be used to reconnect implanted electrodes with the target neural pathways. Conductive hydrogel (CH) electrode coatings have been proposed as a substrate for supporting OEC survival and proliferation at the device interface. To determine an ideal CH to support OECs, this study explored eight CH variants, with differing biochemical composition, in comparison to a conventional Pt electrodes. All CH variants were based on a biosynthetic hydrogel, consisting of poly(vinyl alcohol) and heparin, through which the conductive polymer (CP) poly(3,4-ethylenedioxythiophene) was electropolymerized. The biochemical composition was varied through incorporation of gelatin and sericin, which were expected to provide cell adherence functionality, supporting attachment, and cell spreading. Combinations of these biomolecules varied from 1 to 3 wt %. The physical, electrical, and biological impact of these molecules on electrode performance was assessed. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrated that the addition of these biological molecules had little significant effect on the coating's ability to safely transfer charge. Cell attachment studies, however, determined that the incorporation of 1 wt % gelatin in the hydrogel was sufficient to significantly increase the attachment of OECs compared to the nonfunctionalized CH.
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Affiliation(s)
- Rachelle T Hassarati
- Graduate School of Biomedical Engineering, UNSW Australia, Sydney, Australia.,Bio/polymers Research Group, School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, Australia
| | - Helder Marcal
- Topical Therapeutics Research Group, School of Medical Sciences, Faculty of Medicine, UNSW Australia, Sydney, Australia
| | - L John
- Bio/polymers Research Group, School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, Australia
| | - R Foster
- Bio/polymers Research Group, School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, Australia
| | - Rylie A Green
- Graduate School of Biomedical Engineering, UNSW Australia, Sydney, Australia
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66
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Huang WC, Lai HY, Kuo LW, Liao CH, Chang PH, Liu TC, Chen SY, Chen YY. Multifunctional 3D Patternable Drug-Embedded Nanocarrier-Based Interfaces to Enhance Signal Recording and Reduce Neuron Degeneration in Neural Implantation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:4186-4193. [PMID: 26074252 DOI: 10.1002/adma.201500136] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 05/12/2015] [Indexed: 06/04/2023]
Affiliation(s)
- Wei-Chen Huang
- Department of Materials Science and Engineering, National Chiao Tung University, No. 1001, Ta-Hsueh Rd., Hsinchu, 30010, Taiwan
| | - Hsin-Yi Lai
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, No. 268, Kaixuan Road, Hangzhou City, Zhejiang Province, 310029, China
| | - Li-Wei Kuo
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, No. Keyan Road, Miaoli, 35053, Taiwan
| | - Chia-Hsin Liao
- Department of Medical Research, Buddhist Tzu Chi General Hospital, No. 707, Sec. 3, Chung-Yang Rd., Hualien, 97002, Taiwan
| | - Po-Hsieh Chang
- Department of Materials Science and Engineering, National Chiao Tung University, No. 1001, Ta-Hsueh Rd., Hsinchu, 30010, Taiwan
| | - Ta-Chung Liu
- Department of Materials Science and Engineering, National Chiao Tung University, No. 1001, Ta-Hsueh Rd., Hsinchu, 30010, Taiwan
| | - San-Yuan Chen
- Department of Materials Science and Engineering, National Chiao Tung University, No. 1001, Ta-Hsueh Rd., Hsinchu, 30010, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming University, No. 155, Sec. 2, Linong St., Taipei, 11221, Taiwan
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67
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Zhang D, Di F, Zhu Y, Xiao Y, Che J. Electroactive hybrid hydrogel: Toward a smart coating for neural electrodes. J BIOACT COMPAT POL 2015. [DOI: 10.1177/0883911515591647] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Electroactive hybrid hydrogels, composed of single-walled carbon nanotubes, polypyrrole, and poly(ethylene glycol) diacrylate–polyacrylamide, were synthesized on titanium-mesh electrodes via interfacial polymerization. The modified electrodes can be used as controlled drug delivery system by applying an external electrical stimulation of cyclic voltammetry. Investigations revealed that single-walled carbon nanotubes acted as nucleators in the hybrid hydrogel and facilitated the formation of a continuous and uniform polypyrrole coating. Simultaneous incorporation of single-walled carbon nanotubes and polypyrrole improved not only the electrochemical performance but also the drug loading capacity of the hydrogel. Study of dexamethasone release triggered by cyclic voltammetry indicated that the hybrid hydrogel exhibited good electrochemical stability, a high drug loading capacity, and a linear and sustaining drug release profile, making the modified electrode a novel high-performance drug delivery device. Moreover, in vitro experiments demonstrated that dexamethasone released from the modified electrodes well retained its bioactivity, having the same effect on reducing lipopolysaccharide-induced macrophage activation as the intact commercially available dexamethasone. More important, the obtained modified electrodes possessed good biocompatibility with neural cells, demonstrated by in vitro cell culture.
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Affiliation(s)
- Danying Zhang
- Key Laboratory of Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing, China
| | - Feng Di
- Key Laboratory of Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing, China
| | - Yinyan Zhu
- Collaborative Innovation Center of Biomedical Functional Materials, Nanjing Normal University, Nanjing, China
| | - Yinghong Xiao
- Collaborative Innovation Center of Biomedical Functional Materials, Nanjing Normal University, Nanjing, China
| | - Jianfei Che
- Key Laboratory of Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing, China
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Goding JA, Gilmour AD, Martens PJ, Poole-Warren LA, Green RA. Small bioactive molecules as dual functional co-dopants for conducting polymers. J Mater Chem B 2015; 3:5058-5069. [DOI: 10.1039/c5tb00384a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Scanning electron microscope image of surface morphology of conducting polymer PEDOT doped with bioactive molecules.
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Affiliation(s)
- J. A. Goding
- Graduate School of Biomedical Engineering
- University of New South Wales
- Sydney 2052
- Australia
| | - A. D. Gilmour
- Graduate School of Biomedical Engineering
- University of New South Wales
- Sydney 2052
- Australia
| | - P. J. Martens
- Graduate School of Biomedical Engineering
- University of New South Wales
- Sydney 2052
- Australia
| | - L. A. Poole-Warren
- Graduate School of Biomedical Engineering
- University of New South Wales
- Sydney 2052
- Australia
| | - R. A. Green
- Graduate School of Biomedical Engineering
- University of New South Wales
- Sydney 2052
- Australia
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69
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Sasaki M, Karikkineth BC, Nagamine K, Kaji H, Torimitsu K, Nishizawa M. Highly conductive stretchable and biocompatible electrode-hydrogel hybrids for advanced tissue engineering. Adv Healthc Mater 2014; 3:1919-27. [PMID: 24912988 DOI: 10.1002/adhm.201400209] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 05/21/2014] [Indexed: 11/08/2022]
Abstract
Hydrogel-based, molecular permeable electronic devices are considered to be promising for electrical stimulation and recording of living tissues, either in vivo or in vitro. This study reports the fabrication of the first hydrogel-based devices that remain highly electrically conductive under substantial stretch and bending. Using a simple technique involving a combination of chemical polymerization and electropolymerization of poly (3,4-ethylenedioxythiophene) (PEDOT), a tight bonding of a conductive composite of PEDOT and polyurethane (PU) to an elastic double-network hydrogel is achieved to make fully organic PEDOT/PU-hydrogel hybrids. Their response to repeated bending, mechanical stretching, hydration-dessication cycles, storage in aqueous condition for up to 6 months, and autoclaving is assessed, demonstrating excellent stability, without any mechanical or electrical damage. The hybrids exhibit a high electrical conductivity of up to 120 S cm(-1) at 100% elongation. The adhesion, proliferation, and differentiation of neural and muscle cells cultured on these hybrids are demonstrated, as well as the fabrication of 3D hybrids, advancing the field of tissue engineering with integrated electronics.
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Affiliation(s)
- Masato Sasaki
- Department of Bioengineering and Robotics; Graduate School of Engineering; Tohoku University; 6-6-01 Aoba Sendai 980-8579 Japan
| | - Bijoy Chandapillai Karikkineth
- Department of Bioengineering and Robotics; Graduate School of Engineering; Tohoku University; 6-6-01 Aoba Sendai 980-8579 Japan
| | - Kuniaki Nagamine
- Department of Bioengineering and Robotics; Graduate School of Engineering; Tohoku University; 6-6-01 Aoba Sendai 980-8579 Japan
| | - Hirokazu Kaji
- Department of Bioengineering and Robotics; Graduate School of Engineering; Tohoku University; 6-6-01 Aoba Sendai 980-8579 Japan
| | - Keiichi Torimitsu
- Department of Bioengineering and Robotics; Graduate School of Engineering; Tohoku University; 6-6-01 Aoba Sendai 980-8579 Japan
| | - Matsuhiko Nishizawa
- Department of Bioengineering and Robotics; Graduate School of Engineering; Tohoku University; 6-6-01 Aoba Sendai 980-8579 Japan
- JST-CREST, Sanbancho; Chiyoda-ku Tokyo 102-0075 Japan
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70
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Aregueta-Robles UA, Woolley AJ, Poole-Warren LA, Lovell NH, Green RA. Organic electrode coatings for next-generation neural interfaces. FRONTIERS IN NEUROENGINEERING 2014; 7:15. [PMID: 24904405 PMCID: PMC4034607 DOI: 10.3389/fneng.2014.00015] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 05/06/2014] [Indexed: 01/05/2023]
Abstract
Traditional neuronal interfaces utilize metallic electrodes which in recent years have reached a plateau in terms of the ability to provide safe stimulation at high resolution or rather with high densities of microelectrodes with improved spatial selectivity. To achieve higher resolution it has become clear that reducing the size of electrodes is required to enable higher electrode counts from the implant device. The limitations of interfacing electrodes including low charge injection limits, mechanical mismatch and foreign body response can be addressed through the use of organic electrode coatings which typically provide a softer, more roughened surface to enable both improved charge transfer and lower mechanical mismatch with neural tissue. Coating electrodes with conductive polymers or carbon nanotubes offers a substantial increase in charge transfer area compared to conventional platinum electrodes. These organic conductors provide safe electrical stimulation of tissue while avoiding undesirable chemical reactions and cell damage. However, the mechanical properties of conductive polymers are not ideal, as they are quite brittle. Hydrogel polymers present a versatile coating option for electrodes as they can be chemically modified to provide a soft and conductive scaffold. However, the in vivo chronic inflammatory response of these conductive hydrogels remains unknown. A more recent approach proposes tissue engineering the electrode interface through the use of encapsulated neurons within hydrogel coatings. This approach may provide a method for activating tissue at the cellular scale, however, several technological challenges must be addressed to demonstrate feasibility of this innovative idea. The review focuses on the various organic coatings which have been investigated to improve neural interface electrodes.
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Affiliation(s)
| | - Andrew J. Woolley
- Graduate School of Biomedical Engineering, University of New South WalesSydney, NSW, Australia
- School of Medicine, University of Western SydneySydney, NSW, Australia
| | - Laura A. Poole-Warren
- Graduate School of Biomedical Engineering, University of New South WalesSydney, NSW, Australia
| | - Nigel H. Lovell
- Graduate School of Biomedical Engineering, University of New South WalesSydney, NSW, Australia
| | - Rylie A. Green
- Graduate School of Biomedical Engineering, University of New South WalesSydney, NSW, Australia
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Abstract
Nerve injury secondary to trauma, neurological disease or tumor excision presents a challenge for surgical reconstruction. Current practice for nerve repair involves autologous nerve transplantation, which is associated with significant donor-site morbidity and other complications. Previously artificial nerve conduits made from polycaprolactone, polyglycolic acid and collagen were approved by the FDA (USA) for nerve repair. More recently, there have been significant advances in nerve conduit design that better address the requirements of nerve regrowth. Innovations in materials science, nanotechnology, and biology open the way for the synthesis of new generation nerve repair conduits that address issues currently faced in nerve repair and regeneration. This review discusses recent innovations in this area, including the use of nanotechnology to improve the design of nerve conduits and to enhance nerve regeneration.
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