Chinese Nian Gao Inspired Textured Janus Hydrogel for Body Signal Sensing and Human Machine Interaction

Inspired by Chinese Nian Gao, a traditional food in China, a skin-like bio-hydrogel with asymmetric Janus adhesion and textured structures on its surface is fabricated via a one-pot strategy and is evaluated as electronic skin for sensing and human-machine interaction. The e-skin is constructed through hydrogen bonding and metal-ligand coordination with favorable toughness and stretchability (tensile strength of 173 kPa, strain of 1593%). The bottom surface of the e-skin reached an adhesion strength of 66.7 kPa, and the upper surface shows no adhesion on different substrates, which ensures the stable signal collection on the bottom and avoids interference from incidental contact with clothing or external objects on the upper side. The skin-mimic textures are created in drying, which endows the hydrogel with visual authenticity comparable to biological skin; consequently, it can be used for human scar coverage and skin encapsulation of humanoid robots. The e-skin has an outstanding biocompatibility as well as a high self-healing efficiency of 93.5% and it is developed and demonstrated for multipurpose real-time applications. Furthermore, it accurately identifies hand gestures to control an assistive robotic arm in real-time based on EMG and EEG signals, highlighting its potential in next-generation aesthetic and functional wearable electronics.