Cooking inspired tough, adhesive, and low-temperature tolerant gluten-based organohydrogels for high performance strain sensors

Biomaterial-based flexible gels are attracting considerable interest in the areas of wearable sensors due to their conducive biocompatibility and degradability. However, concurrently integrating conductivity, toughness, adhesiveness, low-temperature tolerance, and self-recovery capability into biomaterial-based gels via simple and low-cost ways is still a great challenge. Herein, conductive reduced graphene oxide (RGO) is successfully introduced into protein networks derived from edible wheat flour dough by simple kneading, washing, and solvent exchange processes. The dense protein networks, diverse functional groups, and potential interactions among components endow the obtained organohydrogels (GGOHx) with favorable toughness (∼1.83 MJ m−3), compatible adhesion toward various materials, and self-recovery capabilities. Moreover, with the help of glycerol, GGOHx exhibit promising water retention and low-temperature tolerance. As wearable strain sensors, GGOHx with sensitive deformation-dependent conductivity can monitor both large-scale human motions (e.g., joint bending) and tiny physiological signals (e.g., swallowing) in the temperature range from −20 °C to 25 °C with long-term stability (>4000 cycles). Therefore, this work may pave a green and simple way for the fabrication of high-performance protein-based strain sensors.