Recent Advances and Prospects in Skin-Integrated Electronics: Flexible Sensing Systems for Robotics, Human-Machine...

Biological skin is among the most sophisticated organs and mediates essential sensory function. Inspired by its structure and function, skin-integrated flexible sensing systems have developed rapidly and demonstrated significant utility in applications such as closed-loop robotic control, human-machine interaction, and health monitoring. These systems typically comprise sensing components and electrodes/circuits for signal acquisition, transmission, and processing, that can provide direct feedback to users or support control signals to actuators. A central objective in this field is the integration of appropriate flexible materials to fabricate functional units that optimally balance response sensitivity and mechanical compliance for special scenarios. This review systematically summarizes sensing components for mechanical stimuli (pressing, stretching, bending, and twisting) and evaluates material selection and optimization strategies according to distinct transduction mechanisms, including capacitive, piezoelectric, resistive, triboelectric effects, etc. Besides, the review investigates the design and layout of flexible signal-acquisition electrodes and processing circuits, and surveys recent progress in deformation-invariant high-conductivity materials. Specific applications in electrophysiological monitoring and physicochemical sensing of biological fluids are discussed in detail. Finally, the review highlights current challenges and future perspectives to guide material development, optimization, and applications of next-generation intelligent electronic skins.