Implantable and Flexible Electronics for In vivo Brain Activity Recordings

Abstract

Implantable electronics are essential for electrophysiological recording at single-neuron and sub-millisecond resolution in the fields of neuroscience and neuroprosthesis. Advances in nano/microfabrication techniques offer new and exciting opportunities for the development of high-density implantable electronics. However, the mechanical mismatch between microfabricated rigid electronics and soft brain tissues has been shown to cause inflammatory responses, leading to signal degradation during chronic recording. Recently, flexible electronics with improved mechanical compatibility to brain tissues have been intensively investigated to improve the performance of chronic neural recordings. Flexible electronics can form conformal interfaces with brain tissue, resulting in minimized inflammatory responses and stable signal recordings. In addition, ultra-small, high-density, and multiple-functionality are also desirable features of flexible neural electronics. In this review, we highlight recent progress in microfabricated flexible electronics for in vivo brain activity recordings, and focus on structural design, brain/tissue interface, implantation method, minimization, and multifunctional integration. Flexible electronics with improved mechanical compatibility to brain tissue have been investigated to minimize inflammatory responses and improve the chronic neural recording. In this review, we highlighted the recent progress in microfabricated flexible electronics for in vivo brain activity recordings, with a focus on novel structure design, implantation method, minimization, integration and stable neural interface.