Abstract

Gold is the most widely used electrode material for bioelectronic applications due to its high electrical conductivity, good chemical stability and proven biocompatibility. However, it adheres only weakly to widely used substrate materials such as glass and silicon oxide, typically requiring the use of a thin layer of chromium between the substrate and the metal to achieve adequate adhesion. Unfortunately, this approach can reduce biocompatibility relative to pure gold films due to the risk of the underlying layer of chromium becoming exposed. Here we report on an alternative adhesion layer for gold and other metals formed from a thin layer of the negative-tone photoresist SU-8, which we find to be significantly less cytotoxic than chromium, being broadly comparable to bare glass in terms of its biocompatibility. Various treatment protocols for SU-8 were investigated, with a view to attaining high transparency and good mechanical and biochemical stability. Thermal annealing to induce partial cross-linking of the SU-8 film prior to gold deposition, with further annealing after deposition to complete cross-linking, was found to yield the best electrode properties. The optimized glass/SU8-Au electrodes were highly transparent, resilient to delamination, stable in biological culture medium, and exhibited similar biocompatibility to glass.

Details

Title
Use of SU8 as a stable and biocompatible adhesion layer for gold bioelectrodes
Author
Matarèse, Bruno F E 1 ; Feyen, Paul L C 2 ; Falco, Aniello 3   VIAFID ORCID Logo  ; Benfenati, Fabio 4 ; Lugli, Paolo 3 ; deMello, John C 1   VIAFID ORCID Logo 

 Imperial College London, Exhibition Road, South Kensington, London, UK 
 Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy 
 Faculty of Science and Technology, Free University of Bolzano - Bozen, Bolzano, Italy 
 Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy; Department of Experimental Medicine, University of Genoa, Genoa, Italy 
Pages
1-12
Publication year
2018
Publication date
Apr 2018
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2021297593
Copyright
© 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.