Skin-mimicking biogel-based iontronic sensor with hierarchical bionic coupling for dexterous tactile e-skin

The human fingertip skin, with its interlocked epidermal-dermal architecture and dense tactile receptors, enables unique perception and inspires the design of innovative electronic skin (e-skin). However, most e-skin materials fail to replicate the hierarchical integration of composition, structure, and function found in natural skin. Drawing direct inspiration from the dermal extracellular matrix-a composite hydrogel reinforced by a collagen-hyaluronic acid, here we report an e-skin that mimics key composition and architectural features of human skin. By incorporating sodium lactate and montmorillonite nanosheets into a gelatin matrix, we engineer a biomimic gel with mechanical and hydration properties similar to those of natural skin through dynamic ionic crosslinking and hydrogen bond networks. The microstructure resembling the dermal papillae is designed using a sandpaper-templating strategy. The resulting iontronic sensor achieves high sensitivity (466.3 kPa^-1), rapid response (47 ms), and a wide pressure detection range (20 Pa-2000 kPa). We further develop a stretchable, ultrathin, hand-shaped iontronic sensor array that integrates seamlessly with a dexterous robotic hand, achieving precise, nondestructive grasping and high-fidelity, multichannel pressure mapping.