Biocompatible, stretchable and mineral PVA–gelatin–nHAP hydrogel for highly sensitive pressure sensors

Conductive hydrogels have attracted increasing attention because of their important application in flexible pressure sensors. However, designing hydrogels with a combination of excellent mechanical properties, high sensitivity, and good biocompatibility is still a profound challenge. Here we report a conductive and biocompatible PVA–Gelatin–nHAP hydrogel (PGHAP gel) by connecting a double network with inorganic nano-particles via ionic bonds. The as-prepared gel achieves excellent elasticity and good fatigue resistance even after 50 cycles of compression. Then a hydrogel pressure sensor was obtained using the as-prepared gel, exhibiting high pressure sensitivity almost linearly responding up to 1.5 kPa and adequate stability of the capacitance–pressure over 4 cycles. These results demonstrate the great potential applications of the hydrogel in biomedical devices, including artificial intelligence, human motion detection, and wearable devices.