Electrode materials for brain–machine interface: A review

Abstract

Brain-machine interface (BMI) is a device that translates neuronal information into commands, which is capable of controlling external software or hardware, such as a computer or robotic arm. In consequence, the electrodes with desirable electrical and mechanical properties for direct interacting between neural tissues and machines serves as the crucial and critical part of BMI technology. Nowadays, the development of material science provides many advanced electrodes for neural stimulating and recording. Particularly, the widespread applications of nanotechnologies have innovatively introduced biocompatible electrode that can have similar characteristics with neural tissue. This paper reviews the existing problems and discusses the latest development of electrode materials for BMI, including conducting polymers, silicon, carbon nanowires, graphene, and hybrid organic-inorganic nanomaterials. In addition, we will inspect at the technical and scientific challenges in the development of neural electrode for a broad application of BMI with focus on the biocompatibility, mechanical mismatch, and electrical performance of electrode materials.

Advanced unconventional techniques for sub‐100 nm nanopatterning

“…However, further exploration of electrical materials and flexible substrates for nanopatterning would be essential for brain-machine interface applications. [163][164][165] Furthermore, molecular-scale patterning and visual representation: assembling building materials at a molecular scale enables fabricated patterns for molecular optoelectronics to be developed. 163,[166][167][168] A critical challenge in sub-10 nm patterning methods is the regular positioning of functional molecules and their integration into the devices.…”

“…Multi‐dimensional structures of sub‐100 nm scale have abundant surface sites that provide higher sensitivity together with faster fault response. However, further exploration of electrical materials and flexible substrates for nanopatterning would be essential for brain–machine interface applications 163–165 …”

Graphene-based implantable neural electrodes for insect flight control

“…[2][3][4][5][6][7] Conventional rigid fiber-like electrodes cannot be competent for long-term implantation due to their excessive elastic modulus. 8 Therefore, there are two main approaches to improving fibrous electrodes' mechanical and electrical properties. The first is to coat the conventional rigid fiber electrode with a soft layer of substances such as conductive polymers (CPs), 9 conductive hydrogels, 10 and so on.…”

Metal-Oxide Nanomaterials Synthesis and Applications in Flexible and Wearable Sensors

“…Recently, flexible electronics including flexible sensors, − power sources, and conductors , have been studied eagerly due to significant advantages in terms of reduced weight, flexibility, and durability to sustain multideformation (i.e., stretching, twisting, bending, and compression) compared with their rigid counterparts. − During this vigorous development, flexible/wearable sensory systems have also been studied with various sensing materials including carbon materials, ,− biomolecules, , conductive polymers, ,, and inorganic nanomaterials ,, to improve their sensitivity, functionality, and stability via diverse strategies.…”