Microfabrication of Implantable, Flexible Neural Probes Towards Bidirectional Interfacing in the Deep Brain

McGlynn, E., Yalagala, B. P. and Heidari, H. (2022) Microfabrication of Implantable, Flexible Neural Probes Towards Bidirectional Interfacing in the Deep Brain. In: 29th IEEE International Conference on Electronics, Circuits and Systems (ICECS 2022), Glasgow, UK, 24-26 October 2022, ISBN 9781665488235 (doi: 10.1109/ICECS202256217.2022.9971103)

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Abstract

Reduced electrode impedance is crucial for neural recording and improved signal-to-noise ratio. This work describes the micro fabrication processes in creating a flexible polyimide-based implantable neural probe for future integration with a CMOS-based closed-loop system. An equivalent circuit model for the fabricated electrodes is produced from electrochemical impedance spectroscopy measurements. The consequences of electrode passivation on the circuit model are discussed. The average impedance of the two electrodes at 1kHz is 80.79±13.94Ω , thanks to the large surface area exposed to the electrolyte. In each case, the charge transfer resistance was less than 20 kΩ , with a double layer capacitance lower than 30 μF . At high frequencies dominated by the solution resistance, the Nyquist plot matches the expected shape for a bare platinum electrode. This characterization is an important step in the fabrication of a closed-loop system, as stimulating circuit designs are informed by the impedance of the accompanying neural probe.

Item Type:Conference Proceedings
Additional Information:E.M. is supported by the Hybrid Enhanced Regenerative Systems (HERMES) project under Horizon 2020 FETPROACT grant number 824164, and the Engineering and Physical Sciences Research Council (EPSRC) DTP number 2279645.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McGlynn, Eve and Yalagala, Mr Bhavani and Heidari, Professor Hadi
Authors: McGlynn, E., Yalagala, B. P., and Heidari, H.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
ISBN:9781665488235
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