An On-Skin-Formed Silk Protein Bioelectrode for Conformable and Robust Electrophysiological Interface

The electrophysiological interface is essential for understanding electrical activities within biological organisms and human-machine interaction. However, traditional preformed bioelectrodes show insufficient interface contact with hairy and irregular skin, causing signal attenuation and distortion. Here, an on-skin-formed silk protein bioelectrode is reported with a conformable and robust interface, achieving a high signal-to-noise ratio for electromyographic signals, showing up to a 38.9% increase compared to traditional ones. The fluid-gel transition of silk protein is induced by a gelling agent composed of ethanol and sodium alginate, leading to a conformable and seamless interface with hairy and irregular human skin, thus resulting in a high signal-to-noise ratio. The developed bioelectrode can record electrophysiological signals stably, even underwater. Additionally, human-machine interaction using electromyographic signals is designed to precisely control the model car's motion trajectory. This work presents an effective method for developing a seamless and conformable electrophysiological interface in bioelectronics.