"All-in-one" hydrolyzed keratin protein-modified polyacrylamide composite hydrogel transducer

Conductive hydrogels as wearable devices meet the basic demands of mechanical flexibility and smart sensing. However, achieving a combination of adequate skin adhesion, long-term stability and visible human-sensor interface are still challengeable. Here, a simple and effective strategy was proposed to fabricate "all-in-one" hydrolyzed keratin protein-modified polyacrylamide composite hydrogel transducer. Hydrolyzed keratin endowed hydrogel with lower modulus and ultra-stretchability to minimize wearing-related tension and discomfort. Specially, robust skin adhesion was obtained to achieve precise sensing without delamination. Impressively, the hydrogel had high transparency and exhibited wide-range temperature tolerance (-20 degrees C to 50 degrees C). Besides, the hydrogel with stable conductivity was extremely sensitive to pressure and strain at a wide range. As a result, the obtained transducer could not only detect human motion, respiratory mode and vocal-cord vibration, but also identify handwriting and facial expression. This work shed a new light on the design of next generation skin-like electronic devices with applications in human-machine interface, ionic skin, artificial intelligence and healthcare monitoring.