A 3D flexible neural interface based on a microfluidic interconnection cable capable of chemical delivery

Yoo Na Kang,Sohee Kim,Namsun Chou,Han Kyoung Choe,Jae-Won Jang

doi:10.1038/s41378-021-00295-6

Abstract

The demand for multifunctional neural interfaces has grown due to the need to provide a better understanding of biological mechanisms related to neurological diseases and neural networks. Direct intracerebral drug injection using microfluidic neural interfaces is an effective way to deliver drugs to the brain, and it expands the utility of drugs by bypassing the blood–brain barrier (BBB). In addition, uses of implantable neural interfacing devices have been challenging due to inevitable acute and chronic tissue responses around the electrodes, pointing to a critical issue still to be overcome. Although neural interfaces comprised of a collection of microneedles in an array have been used for various applications, it has been challenging to integrate microfluidic channels with them due to their characteristic three-dimensional structures, which differ from two-dimensionally fabricated shank-type neural probes. Here we present a method to provide such three-dimensional needle-type arrays with chemical delivery functionality. We fabricated a microfluidic interconnection cable (µFIC) and integrated it with a flexible penetrating microelectrode array (FPMA) that has a 3-dimensional structure comprised of silicon microneedle electrodes supported by a flexible array base. We successfully demonstrated chemical delivery through the developed device by recording neural signals acutely from in vivo brains before and after KCl injection. This suggests the potential of the developed microfluidic neural interface to contribute to neuroscience research by providing simultaneous signal recording and chemical delivery capabilities.

Highlights

With the development of micromachined neural interfaces, various multifunctional neural interfacing systems have been introduced for different applications[1,2,3,4,5]
Takeuchi et al fabricated a parylene-C (PPX-C)-based flexible neural probe integrated with microfluidic channels[20], which was inserted into a rat brain with the help of supporting materials such as polyethylene glycol (PEG)
We propose a 3dimensional, flexible, and multifunctional neural interface based on an flexible penetrating microelectrode array (FPMA) integrated with a PPX-C-based microfluidic interconnection cable to deliver chemicals to the electrodes (Fig. 1a)

Summary

Introduction

With the development of micromachined neural interfaces, various multifunctional neural interfacing systems have been introduced for different applications[1,2,3,4,5]. Takeuchi et al fabricated a parylene-C (PPX-C)-based flexible neural probe integrated with microfluidic channels[20], which was inserted into a rat brain with the help of supporting materials such as polyethylene glycol (PEG).

Results

Conclusion