Multifunctional monolithic gold nanowires for wireless smart wearable personalized healthcare device.

Despite extensive investigation on soft bioelectronic systems for smart healthcare, it remains a big technical challenge to achieve robust, wireless integration of multifunctional components via monolithic patterning. Here, we developed a wireless wearable healthcare device fabricated using bulk and hollow gold nanowires (Ag@AuNW and AuHNW) with distinct electrical properties. The strain sensor based on AuHNW showed high sensitivity (ΔR/R0 = 773.07 at 100 %) and the Ag@AuNW-based temperature sensor showed superior temperature sensitivity (0.296 % oC-1). Both sensors exhibited remarkable selectivity with minimal cross-sensitivity to strain, pressure, and temperature, and the heater remained stable under mechanical deformation (ΔT = 1.61 °C at 20 % strain). In particular, the nanomaterials in the system showed high biocompatibility with high cell viability over 90 %, and robust stability under chemical (immersion in oxidative and humid) and mechanical (2000 cycles of stretching) test conditions. These components were monolithically patterned onto a single stretchable platform integrating sensors, a heater, circuits, and a wireless module. With a mobile application, the system enabled the real-time monitoring of temperature and motion (finger, neck, elbow, and tiny muscle movement), along with on-demand thermal heating. Taken together, this wireless multifunctional smart wearable device would be successfully harnessed as a next-generation platform for personalized healthcare applications.