Interpenetrating Conducting Hydrogel Materials for Neural Interfacing Electrodes. Issue 9 (15th February 2017)

• Record Type: Journal Article
• Authors: Goding, Josef; Gilmour, Aaron; Martens, Penny; Poole‐Warren, Laura; Green, Rylie
• Is Part Of: Advanced healthcare materials. Volume 6:Issue 9(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-02-15
• Subjects: conductive hydrogel -- conductive polymer -- hydrogel -- interpenetrating networks -- neural electrodes; Biomedical materials -- Periodicals; 610.28
• DOI: 10.1002/adhm.201601177
• Languages: English
• ISSNs: 2192-2640

Abstract

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. Abstract : Hybridization of conducting polymers and hydrogels to form interpenetrating networks can be encouraged and controlled through the functionalization of hydrogel macromers with covalently linked, ionic doping groups. The resultant high‐quality conducting hydrogels enable neuroprosthetic devices to use smaller electrodes with greater selectivity, reduced impedance, and lower power consumption compared to traditional metal electrodes.