Neural microprobe modelling and microfabrication for improved implantation and mechanical failure mitigation

McGlynn, E., Walton, F. , Das, R. and Heidari, H. (2022) Neural microprobe modelling and microfabrication for improved implantation and mechanical failure mitigation. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 380(2228), 20210007. (doi: 10.1098/rsta.2021.0007)

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Abstract

Careful design and material selection are the most beneficial strategies to ensure successful implantation and mitigate the failure of a neural probe in the long term. In order to realize a fully flexible implantable system, the probe should be easily manipulated by neuroscientists, with the potential to bend up to 90°. This paper investigates the impact of material choice, probe geometry, and crucially, implantation angle on implantation success through finite-element method simulations in COMSOL Multiphysics followed by cleanroom microfabrication. The designs introduced in this paper were fabricated using two polyimides: (i) PI-2545 as a release layer and (ii) photodefinable HD-4110 as the probe substrate. Four different designs were microfabricated, and the implantation tests were compared between an agarose brain phantom and lamb brain samples. The probes were scanned in a 7 T PharmaScan MRI coil to investigate potential artefacts. From the simulation, a triangular base and 50 µm polymer thickness were identified as the optimum design, which produced a probe 57.7 µm thick when fabricated. The probes exhibit excellent flexibility, exemplified in three-point bending tests performed with a DAGE 4000Plus. Successful implantation is possible for a range of angles between 30° and 90°. This article is part of the theme issue ‘Advanced neurotechnologies: translating innovation for health and well-being’.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Walton, Mr Finlay and McGlynn, Eve and Heidari, Professor Hadi and Das, Dr Rupam
Authors: McGlynn, E., Walton, F., Das, R., and Heidari, H.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
Publisher:Royal Society
ISSN:1364-503X
ISSN (Online):1471-2962
Copyright Holders:Copyright © 2022 The Royal Society
First Published:First published in Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 380(2228):20210007
Publisher Policy:Reproduced under a Creative Commons licence

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
312561EPSRC DTP 2020/21Christopher PearceEngineering and Physical Sciences Research Council (EPSRC)EP/T517896/1Research and Innovation Services
303466HERMESHadi HeidariEuropean Commission (EC)824164ENG - Electronics & Nanoscale Engineering
309079Wireless and Scalable Optogenetics for Neurological Disorders CureHadi HeidariEuropean Commission (EC)893822ENG - Electronics & Nanoscale Engineering