Fabrication of Highly-Porous Stress-Free 3D-Compatible Flexible Neural Probes

Abstract

Research has shown that in vitro neurons grown in three dimensions more closely resemble neurons in vivo, in terms of morphology and behavior, than do those grown in two dimensions. The fabrication of a functional three-dimensional multielectrode array (MEA) would provide a better model with which to research the electrical activity of biological neural networks. However, prior work in this area has either failed to provide true three-dimensional indexing or relied on the use of materials that risk damage to neurons.

This project, started in 2015, attempts to fill this gap with the design of two-dimensional multielectrode arrays fabricated on flexible thin-film polyimide substrate, which can be layered to provide three-dimensional indexing. Current work on the project has resulted in the development of a fabrication recipe for a multielectrode array encapsulated with parylene-C, a biocompatible dielectric polymer that deposits at ambient temperature. We subsequently cultivated rat superior cervical ganglion (SCG) neurons on the surface of our fabricated MEAs, and detected neural signal on flexible polyimide substrate for the first time in project history.