Soft Conductive Nanocomposites for Skin-interfaced Physiological Monitoring

The rising demand for personalized healthcare has accelerated the development of skin-interfaced sensors that are capable of real-time physiological monitoring, early disease detection, and individualized health management. These devices enable the continuous and high-fidelity tracking of diverse physiological signals, such as cardiac activity, muscle contractions, respiration, and temperature, by closely conforming to the complex and dynamic surface of the human skin. However, conventional sensors fabricated from rigid and brittle materials have poor conformability, mechanical mismatch, and reduced user comfort, thus leading to unreliable signal acquisition and limited long-term usability. Soft conductive nanocomposites have emerged as a promising alternative to conventional sensors. The nanocomposites provide tunable electrical conductivity, mechanical compliance, and biocompatibility by integrating conductive nanofillers into stretchable elastomeric matrices. The filler composition, dispersion, and microstructure of these materials can be optimized to closely match the mechanical properties of the skin while maintaining stable electrical performance under deformation. This review provides a comprehensive overview of recent advances in soft conductive nanocomposites for skin-interfaced physiological monitoring, organized by widely used nanoscale and microscale fillers including metallic, carbon-based, liquid metal, and ionic materials. Furthermore, this review examines how conductive fillers affect the percolation behavior and electromechanical performance of conductive nanocomposites. We highlight representative applications in monitoring the electrical and mechanical form of physiological signals. Finally, we present future research directions aimed at advancing these materials toward next-generation wearable and biointegrated electronics for personalized healthcare.