Electron Conductive and Transparent Hydrogels for Recording Brain Neural Signals and Neuromodulation.

Recording brain neural signals and optogenetic neuromodulations open frontiers in decoding brain neural information and neurodegenerative diseases therapeutics. Conventional implantable probes suffer from modulus mismatch with biological tissues and an irreconcilable tradeoff between transparency and electron conductivity. Herein, a strategy was proposed to address these tradeoffs, which generates conductive and transparent hydrogels with polypyrrole-decorated microgels as crosslinkers. The optical transparency of the electrodes can be attributed to the special structures that allow light waves to bypass the microgel particles and minimize their interaction. Demonstrated by probing the hippocampus of rat brains, the biomimetic electrode shows a prolonged capacity for simultaneous optogenetic neuromodulation and recording of brain neural signals. More importantly, an intriguing brain-machine interaction was realized, which involved signal input to the brain, brain neural signal generation, and controlling limb behaviors. This breakthrough work represents a significant scientific advancement toward decoding brain neural information and in neurodegenerative disease therapy. This article is protected by copyright. All rights reserved.