With increasing interest and demand for wearable sensor devices, fabricating a flexible hydrogel sensor combining

high toughness and adhesiveness is necessary but remains challenging. In this work, inspired by the

delamination structure of skin, an ultra-stretchable wearable hydrogel strain sensor with double layers is successfully

prepared via in-situ polymerization of nucleobase-driven adhesive hydrogels on the surface of conductive

tough hydrogels crosslinked by hydrophobic association. The hydrogel exhibits ultra-stretchability, high

mechanical strength, and robust adhesion to various solid materials as well as skin. Furthermore, the hydrogel

also exhibits high strain sensitivity and stability as a flexible and wearable strain sensor to detect large-range

human motions and tiny physiological signals. Notably, the adhesive layer not only ensures a robust adhesion

between the sensors and skin, but also protects skin from current harm when the hydrogels contact with skin

directly, because of effectively blocking the current from the conductive tough layer. It is envisioned that the

skin-inspired strategy would provide novel inspiration for the development of hydrogel strain sensors.