Stretchable, Bio-Compatible, Antioxidant and Self-Powering Adhesives from Soluble Silk Fibroin and Vegetal Polyphenols Exfoliated Graphite

The development of bio-glues is still a challenging task, regarding adhesion on wet surfaces; often, high performance and adaption to complex geometries need to be combined in one material. Here, we report biocompatible adhesives obtained by blending regenerated silk (RS) with a soluble plant-derived polyphenol (i.e., chestnut tannin) that was also used to exfoliate graphite to obtain graphene-based RS/tannin (G-RS/T) composites. The resultant G-RS/T hybrid material exhibited outstanding stretchability (i.e., 400%) and high shear strength (i.e., 180 kPa), superior to that of commercial bio-glues, and showed sealant properties for tissue approximation. Moreover, we showed how such nanocomposites exhibit electromechanical properties that could potentially be used for the realization of green and eco-friendly piezoelectric devices. Finally, we demonstrate the in vitro glue's biocompatibility and anti-oxidant properties that enable their utilization in clinical applications.