A flexible three-dimensional electrode mesh: An enabling technology for wireless brain–computer interface prostheses

Abstract

The neural interface is a key component in wireless brain-computer prostheses. In this study, we demonstrate that a unique three-dimensional (3D) microneedle electrode on a flexible mesh substrate, which can be fabricated without complicated micromachining techniques, is conformal to the tissues with minimal invasiveness. Furthermore, we demonstrate that it can be applied to different functional layers in the nervous system without length limitation. The microneedle electrode is fabricated using drawing lithography technology from biocompatible materials. In this approach, the profile of a 3D microneedle electrode array is determined by the design of a two-dimensional (2D) pattern on the mask, which can be used to access different functional layers in different locations of the brain. Due to the sufficient stiffness of the electrode and the excellent flexibility of the mesh substrate, the electrode can penetrate into the tissue with its bottom layer fully conformal to the curved brain surface. Then, the exposed contact at the end of the microneedle electrode can successfully acquire neural signals from the brain. INTRODUCTIONBrain-computer prostheses provide a bridge for humans to understand and communicate with the nervous system. Neural interfaces are a key component enabling wireless brain-computer prostheses for long-term implantation. In the last decades, researchers have developed various types of neural interfaces based on advanced functional materials and fabrication technology [1][2][3] . Because a two-dimensional (2D) structure can be shaped precisely and easily, most neural interfaces are fabricated into planar geometries, which are known as neural probes. However, neural tissues are normally three-dimensional (3D) structures, and 2D neural probes are limited to recording signals from only planar brain regions

Photothermally Triggered Shape‐Adaptable 3D Flexible Electronics

“…More recent work has proven that flexible electrodes fabricated on polymer substrates, such as polyimide (PI), polydimethylsiloxane and parylene‐C, can reduce deleterious tissue responses . However, shape adaptation remains a challenge to ensure the prolonged stability on complex surfaces, which are most often 3D, such as skin, tissues, and organs . As a solution, researchers have focused on the novel design of electrodes or the integration of soft materials .…”

Tunable fractional Fourier transform implementation of electronic wave functions in atomically thin materials

“…Electrode arrays with convex or concave geometries have been fabricated on flexible substrates for the purpose of acting as brain–computer interfaces [21], while single nanoscale nonplanar electrodes with complex topographies have been obtained using advanced stencil lithography [22]. …”

Unilateral Laryngeal Pacing System and Its Functional Evaluation

“…And needle electrodes we used in the experiment have side effects to muscles. We would use flexible electrodes [31–33] to ensure good biocompatibility and minimal side effects in the future long term pacing. Fourth, PCA was stimulated to generate abduction (not adduction) of paralyzed vocal fold in our current experiment, which aims to achieve synchronous movement of the vocal cords.…”