Development of Adhesive and Conductive Resilin-Based\nHydrogels for Wearable Sensors

Abstract

Integrating\nmultifunctionality such as stretchability, adhesiveness,\nand electroconductivity on a single protein hydrogel is highly desirable\nfor various applications, and remains a challenge. Here we present\nthe development of such multifunctional hydrogels based on resilin,\na natural rubber-like material with remarkable extensibility and resilience.\nFirst, genetically engineered reslin-like proteins (RLPs) with varying\nmolecular weight were biosynthesized to tune mechanical strength and\nstiffness of the cross-linked RLP hydrogels. Second, glycerol was\nincorporated into the hydrogels to endow adhesive properties. Next,\na graphene–RLP conjugate was synthesized for cross-linking\nwith the unmodified, pristine RLP to form an integrated network. The\nobtained hybrid hydrogel could be stretched to over four times of\nits original length, and self-adhered to diverse substrate surfaces\ndue to its high adhesion strength of ∼24 kPa. Furthermore,\nthe hybrid hydrogel showed high sensitivity, with a gauge factor of\n3.4 at 200% strain, and was capable of real-time monitoring human\nactivities such as finger bending, swallowing, and phonating. Due\nto these favorable attributes, the graphene/resilin hybrid hydrogel\nwas a promising material for use in wearable sensors. In addition,\nthe above material design and functionalization strategy may provide\nintriguing opportunities to generate innovative materials for broad\napplications.