Cleanroom strategies for micro- and nano-fabricating flexible implantable neural electronics

Walton, F., Cerezo Sanchez, M., McGlynn, E., Das, R. and Heidari, H. (2022) Cleanroom strategies for micro- and nano-fabricating flexible implantable neural electronics. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 380(2228), 20210009. (doi: 10.1098/rsta.2021.0009) (PMID:35658678) (PMCID:PMC9168450)

Abstract

Implantable electronic neural interfaces typically take the form of probes and are made with rigid materials such as silicon and metals. These have advantages such as compatibility with integrated microchips, simple implantation and high-density nanofabrication but tend to be lacking in terms of biointegration, biocompatibility and durability due to their mechanical rigidity. This leads to damage to the device or, more importantly, the brain tissue surrounding the implant. Flexible polymer-based probes offer superior biocompatibility in terms of surface biochemistry and better matched mechanical properties. Research which aims to bring the fabrication of electronics on flexible polymer substrates to the nano-regime is remarkably sparse, despite the push for flexible consumer electronics in the last decade or so. Cleanroom-based nanofabrication techniques such as photolithography have been used as pattern transfer methods by the semiconductor industry to produce single nanometre scale devices and are now also used for making flexible circuit boards. There is still much scope for miniaturizing flexible electronics further using photolithography, bringing the possibility of nanoscale, non-invasive, high-density flexible neural interfacing. This work explores the fabrication challenges of using photolithography and complementary techniques in a cleanroom for producing flexible electronic neural probes with nanometre-scale features.

• Item Type: Articles
• Additional Information: This work was partially supported by the European Union's Horizon 2020 Hybrid Enhanced Regenerative Medicine Systems (HERMES) project (GA n. 824164) and MSCA-IF WiseCure Project (GA n. 893822). FW is supported by the Engineering and Physical Sciences Research Council (EPSRC) Doctoral Prize Research Fellowship 'Scalable Controlled Treatment impLAntables for Neurological Disorders' (SCOTLAND) under Grant EP/T517896/1. MC-S is supported by HERMES and EM is supported by the EPSRC DTP Grant (2279645).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: McGlynn, Eve and WALTON, Finlay and Das, Dr Rupam and Cerezo Sanchez, Maria and Heidari, Professor Hadi
• Authors: Walton, F., Cerezo Sanchez, M., McGlynn, E., Das, R., and Heidari, H.
• College/School: College of Science and Engineering; 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
• Published Online: 06 June 2022
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 380(2228):20210009
• Publisher Policy: Reproduced under a Creative Commons licence

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
312561		EPSRC DTP 2020/21	Christopher Pearce	Engineering and Physical Sciences Research Council (EPSRC)	EP/T517896/1	Research and Innovation Services