A high-adhesive and sensitive hydrogel with interpenetrating and interlocking networked structure for efficient biological signal monitoring

Smart flexible sensing materials and devices for wearable health monitoring, are considered as prospective and promising areas in healthcare that are currently in high demand in the market. Conductive hydrogel-based sensors, which closely resemble human tissue, encounter notable challenges in attaining high electronic conduction, robust mechanical properties, biocompatibility, and intimate tissue adhesion simultaneously. In this work, a poly(2-acrylamide-2-methylpropane sulfonic acid-co-acrylamide)/bacterial cellulose (P(AMPS-co-AM)/BC) hydrogel with a particular interpenetrating and interlocking networked structure is reported. This hydrogel possesses all the mentioned intriguing properties plus easy degradability. It is realized by utilizing the interaction between amino, amide, and sulfonic groups on polymer molecular chains and polyhydroxy groups on bacterial cellulose. This hydrogel exhibits high strength (1.28 MPa) and tensile strain (525%), remarkable tissue adhesion (697 kPa), exceptional antibacterial property and low cytotoxicity. Furthermore, it can degrade in the natural environment when exposed to UV light irradiation. The hydrogel-based strain sensors have demonstrated efficient human motion detection with a broad strain detection range (0-360%) and a high sensitivity (GF=11.36). Moreover, this hydrogel can be assembled into Triboelectric Nanogenerator for monitoring biological signals. This work presents a new avenue for human-machine interaction and electronic robotic skins.