High‐Density Stretchable Electrode Grids for Chronic Neural Recording

TLDR

Electrical interfacing with neural tissue is essential for diagnosis, therapy, and detailed neural signal acquisition, yet long‑term stability is hindered by a large mechanical mismatch between electronics and tissue, and current materials and fabrication methods limit the creation of soft, high‑density electrode grids. The study aims to overcome this mismatch by creating a soft, high‑density, stretchable electrode grid composed of gold‑coated titanium dioxide nanowires embedded in silicone. The grid is fabricated from an inert, high‑performance composite of gold‑coated TiO₂ nanowires in a silicone matrix, enabling high electrode density and stretchability. In freely moving rats, the grid reliably records high‑spatiotemporal cortical signals for three months with stable quality and preserved coherence, while its flexibility allows a smaller craniotomy and suggests broad biomedical applicability.

Abstract

Electrical interfacing with neural tissue is key to advancing diagnosis and therapies for neurological disorders, as well as providing detailed information about neural signals. A challenge for creating long-term stable interfaces between electronics and neural tissue is the huge mechanical mismatch between the systems. So far, materials and fabrication processes have restricted the development of soft electrode grids able to combine high performance, long-term stability, and high electrode density, aspects all essential for neural interfacing. Here, this challenge is addressed by developing a soft, high-density, stretchable electrode grid based on an inert, high-performance composite material comprising gold-coated titanium dioxide nanowires embedded in a silicone matrix. The developed grid can resolve high spatiotemporal neural signals from the surface of the cortex in freely moving rats with stable neural recording quality and preserved electrode signal coherence during 3 months of implantation. Due to its flexible and stretchable nature, it is possible to minimize the size of the craniotomy required for placement, further reducing the level of invasiveness. The material and device technology presented herein have potential for a wide range of emerging biomedical applications.