Bioinspired tough, conductive hydrogels with thermally reversible adhesiveness based on nanoclay confined NIPAM polymerization and a dopamine modified polypeptide

Hydrogels with excellent conductivity and flexibility have a wide range of applications in the biomedical field, such as in wearable devices, soft electronic skins, and biosensors. Inspired by marine mussels, a biocompatible hydrogel with controllable adhesiveness and a wearable strain-sensor were successfully prepared by polymerization of N-isopropylacrylamide (NIPAM) and a dopamine-modified polypeptide (PDAEA). The PNIPAM-clay-PDAEA hydrogel displayed repeatable and controllable adhesiveness due to the presence of free catechol groups in the PDAEA chains and the intrinsic thermo-sensitivity of the PNIPAM-based hydrogel. These materials also exhibited outstanding strain and pressure sensitive conductivity, which could be ascribed to a sufficient number of free moving ions in the hydrogel system. Test results showed that these conductive hydrogels possessed excellent biocompatibility, stable drug release behavior, and improved cell proliferation. Therefore, the as-prepared nanocomposite hydrogel has great potential applications as a wearable soft electronic skin and in tissue engineering.