High-density individually addressable platinum nanoelectrodes for biomedical applications

Raj, V. , Gopakumar, A., Vaidya, G., Scott, J., Toth, M., Jagadish, C. and Gautam, V. (2022) High-density individually addressable platinum nanoelectrodes for biomedical applications. Discover Materials, 2(1), 6. (doi: 10.1007/s43939-022-00027-1)

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3-D vertical nanoelectrode arrays (NEAs) have found applications in several biomedical and sensing applications, including high-resolution neuronal excitation and measurement and single-molecule electrochemical biosensing. There have been several reports on high-density nanoelectrodes in recent years, with the filling ratio of electrodes reaching close to 0.002 (assuming the electrode diameter of 200 nm and pitch of 4 μm). Still, it is well below the nanowire filling ratio required to form interconnected neuronal networks, i.e., more than 0.14 (assuming the electrode diameter of 200 nm and pitch of 1.5 μm). Here, we employ a multi-step, large-area electron beam lithography procedure along with a targeted, focused ion beam based metal deposition technique to realize an individually addressable, 60-channel nanoelectrode chip with a filling ratio as high as 0.16, which is well within the limit required for the formation of interconnected neuronal networks. Moreover, we have designed the NEA chip to be compatible with the commercially available MEA2100-System, which can, in the future, enable the chip to be readily used for obtaining data from individual electrodes. We also perform an in-depth electrochemical impedance spectroscopy characterization to show that the electrochemical behavior and the charge transfer mechanism in the array are significantly influenced by changing the thickness of the SU-8 planarization layer (i.e., the thickness of the exposed platinum surface). In addition to neural signal excitation and measurement, we propose that these NEA chips have the potential for other future applications, such as high-resolution single-molecule level electrochemical and bio-analyte sensing.

Item Type:Articles
Additional Information:Dementia Australia Research Foundation (DARF) and Yulgilbar Foundation are gratefully acknowledged for their financial support. Dr. Gautam also acknowledges the support from the Australian Research Council’s Discovery Early Career Researcher Award DE180100775.
Glasgow Author(s) Enlighten ID:Raj, Dr Vidur
Authors: Raj, V., Gopakumar, A., Vaidya, G., Scott, J., Toth, M., Jagadish, C., and Gautam, V.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Discover Materials
ISSN (Online):2730-7727
Copyright Holders:Copyright © 2022 The Authors
First Published:First published in Discover Materials 2(1):6
Publisher Policy:Reproduced under a Creative Commons License

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