Fully Bio‐Based Gelatin Organohydrogels via Enzymatic Crosslinking for Sustainable Soft Strain and Temperature Sensing

Abstract Developing soft materials that integrate mechanical compliance, functional responsiveness, and environmental sustainability is key for next‐generation wearable and implantable electronics. Here, a sustainable, fully bio‐based organohydrogel sensor made entirely from food‐grade and biodegradable components, including gelatin, microbial transglutaminase (TG), and glycerol, prepared via a simple one‐pot process under mild thermal conditions, is reported. In this system, TG enzymatically crosslinks gelatin chains into a robust covalent network, while glycerol enhances flexibility, stabilizes hydration, and facilitates proton conduction. The multicomponent system reveals a tunable network morphology governed by enzymatic crosslinking density. The resulting gels exhibit remarkable stretchability (up to 450%), linear strain sensitivity up to 300%, and a high gauge factor of 2.86—placing them among the top‐performing hydrogel‐based strain sensors to date. In addition to strain sensing, the material shows strong thermal responsivity (0.26 °C −1 in the 20–45 °C range) without being affected by variations in environmental humidity. Long‐term electromechanical stability is demonstrated over 5000 cycles. Unlike conventional soft sensors that rely on synthetic polymers, fillers, or dopants, this platform entirely uses food‐safe components and a simple one‐pot process—offering a scalable and sustainable route to soft electronics. These findings establish enzyme‐guided polymer engineering as a powerful tool for functional material design.