Towards a Microfabricated Flexible Graphene-Based Active Implant for Tissue Monitoring During Optogenetic Spinal Cord Stimulation

Conference paper (2020)

Authors

A. Velea Bio-Electronics - EEMCS
S. Vollebregt Electronic Components, Technology and Materials - EEMCS
T.B. Hosman Bio-Electronics - EEMCS , Fraunhofer Institute for Reliability and Microintegration IZM
A. Pak Bio-Electronics - EEMCS , Fraunhofer Institute for Reliability and Microintegration IZM
Vasiliki Giagka Fraunhofer Institute for Reliability and Microintegration IZM, Bio-Electronics - EEMCS
Research Group
Bio-Electronics (EEMCS) (TU Delft)
Copyright: © 2020 A. Velea, S. Vollebregt, T.B. Hosman, A. Pak, Vasiliki Giagka
DOI
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https://doi.org/10.1109/NMDC47361.2019.9084021
Graphene PDMS Neural interface Optogenetic stimulation Transparent active implant
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Published Date

2020-10

Language

English

Reuse Rights

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Bio-Electronics

Abstract

This work aims to develop a smart neural interface with transparent electrodes to allow for electrical monitoring of the site of interest during optogenetic stimulation of the spinal cord. In this paper, a microfabrication process for the wafer-level development of such a compact, active, transparent and flexible implant is presented. Graphene has been employed to form the transparent array of electrodes and tracks, on top of which chips have been bonded using flip-chip bonding techniques. To provide high flexibility, soft encapsulation, using polydimethylsiloxane (PDMS) has been used. Making use of the "Flex-to-Rigid" (F2R) technique, cm-size graphene-on-PDMS structures have been suspended and characterized using Raman spectroscopy to qualitatively evaluate the graphene layer, together with 2-point measurements to ensure the conductivity of the structure. In parallel, flip-chip bonding processes of chips on graphene structures were employed and the 2-point electrical measurement results have shown resistance values in the range of kΩ for the combined tracks and ball-bonds.