Highly Flexible Precisely Braided Multielectrode Probes and Combinatorics for Future Neuroprostheses.

Taegyo Kim,Hualou Liang,Kendall Schmidt,Joanna Wycech,Christopher Deemie,Simon F Giszter

doi:10.3389/fnins.2019.00613

Abstract

The braided multielectrode probe (BMEP) is an ultrafine microwire bundle interwoven into a precise tubular braided structure, which is designed to be used as an invasive neural probe consisting of multiple microelectrodes for electrophysiological neural recording and stimulation. Significant advantages of BMEPs include highly flexible mechanical properties leading to decreased immune responses after chronic implantation in neural tissue and dense recording/stimulation sites (24 channels) within the 100–200 μm diameter. In addition, because BMEPs can be manufactured using various materials in any size and shape without length limitations, they could be expanded to applications in deep central nervous system (CNS) regions as well as peripheral nervous system (PNS) in larger animals and humans. Finally, the 3D topology of wires supports combinatoric rearrangements of wires within braids, and potential neural yield increases. With the newly developed next generation micro braiding machine, we can manufacture more precise and complex microbraid structures. In this article, we describe the new machine and methods, and tests of simulated combinatoric separation methods. We propose various promising BMEP designs and the potential modifications to these designs to create probes suitable for various applications for future neuroprostheses.

Highlights

Tissue response, yield and longevity of invasive neuroprosthetics continue to be issues limiting both basic and clinical deployment and use of current prosthetic designs
Our initial designs supported classical tubular braids. With these we have shown significant gains in compliance compared to some standard methods (Kim et al, 2013), demonstrated chronic recordings in spinal cord of jumping frogs (Kim et al, 2013), and reduced tissue response in rat cortex (Kim et al, 2019)
We combined custom aluminum parts fabricated by a machine shop and purchased commercial mechanical parts with plastic parts printed by our own 3D printer

Summary

Introduction

Yield and longevity of invasive neuroprosthetics continue to be issues limiting both basic and clinical deployment and use of current prosthetic designs. Important factors influence tissue response and longevity, such as mechanical tissue interactions and tissue strain, the size of elements introduced and resulting diffusion barriers. These may all figure as design factors in advances toward successful long term implementation of invasive neuroprosthetics. These factors can plague both electrical and optical methods of recording and stimulation. Various methods have been explored to manage these factors, by both miniaturizing (Szarowski et al, 2003; Seymour and Kipke, 2007; Kozai et al, 2012) and altering compliance of implanted neuroprosthetics (Szarowski et al, 2003; Seymour and Kipke, 2007; Ware et al, 2012; Chamanzar et al, 2014; Sohal et al, 2016).

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Results

Conclusion