The post title is a copy and paste from the title of the linked popular press article here:

> Elon Musk unveils Neuralink’s plans for brain-reading ‘threads’ and a robot to insert them

Journal Reference:

A microfabricated, 3D-sharpened silicon shuttle for insertion of flexible electrode arrays through dura mater into brain

Hannah R Joo1, Jiang Lan Fan2, Supin Chen3, Jeanine A Pebbles4, Hexin Liang5, Jason E. Chung1, Allison M Yorita4, Angela Tooker4, Vanessa Tolosa3, Charlotte Geaghan-Breiner6, Demetris Roumis1, Daniel Liu1, Razi Haque4 and Loren Frank1

Author affiliations

1 University of California San Francisco, San Francisco, California, UNITED STATES

2 Bioengineering, University of California Berkeley, Berkeley, California, UNITED STATES

3 Neuralink Co, San Francisco, California, UNITED STATES

4 Lawrence Livermore National Laboratory, Livermore, California, UNITED STATES

5 UCSF, San Francisco, California, 94143, UNITED STATES

6 Physiology, University of California San Francisco, San Francisco, California, UNITED STATES

Journal of Neural Engineering 2019

Link: https://iopscience.iop.org/article/10.1088/1741-2552/ab2b2e

DOI: https://doi.org/10.1088/1741-2552/ab2b2e

Abstract

Objective. Electrode arrays for chronic implantation in the brain are a critical technology in both neuroscience and medicine. Recently, flexible, thin-film polymer electrode arrays have shown promise in facilitating stable, single-unit recordings spanning months in rats. While array flexibility enhances integration with neural tissue, it also requires removal of the dura mater, the tough membrane surrounding the brain, and temporary bracing to penetrate the brain parenchyma. Durotomy increases brain swelling, vascular damage, and surgical time. Insertion using a bracing shuttle results in additional vascular damage and brain compression, which increase with device diameter; while a higher-diameter shuttle will have a higher critical load and more likely penetrate dura, it will damage more brain parenchyma and vasculature. One way to penetrate the intact dura and limit tissue compression without increasing shuttle diameter is to reduce the force required for insertion by sharpening the shuttle tip. Approach. We describe a novel design and fabrication process to create silicon insertion shuttles that are sharp in three dimensions and can penetrate rat dura, for faster, easier, and less damaging implantation of polymer arrays. Sharpened profiles are obtained by reflowing patterned photoresist, then transferring its sloped profile to silicon with dry etches. Main results. We demonstrate that sharpened shuttles can reliably implant polymer probes through dura to yield high quality single unit and local field potential recordings for at least 90 days. On insertion directly through dura, tissue compression is minimal. Significance. This is the first demonstration of a rat dural-penetrating array for chronic recording. This device obviates the need for a durotomy, reducing surgical time and risk of damage to the blood-brain barrier. This is an improvement to state-of-the-art flexible polymer electrode arrays that facilitates their implantation, particularly in multi-site recording experiments. This sharpening process can also be integrated into silicon electrode array fabrication.