Bionic Structural Design of Multifunctional Flexible Polypyrrole Sensors for Human Health Monitoring.

Rehabilitation medicine is an essential component of universal health coverage, while emerging electronic skin offers new opportunities for portable and personalized healthcare. However, flexible pressure sensors still face trade-offs among sensitivity, detection range, and stability, and gas sensors remain challenged by low-concentration detection and environmental robustness. Herein, a biomimetic "Thalia dealbata" microstructured hydrophobic polypyrrole/polydimethylsiloxane (S@PPy/PDMS) composite sensor was fabricated through a one-step template method and controllable in situ polymerization. The biomimetic PDMS microstructure enhances pressure response, while conductive and NH3-sensitive PPy enables dual-mode pressure and gas sensing on a single flexible platform. The sensor exhibits a wide pressure range of 0-25 kPa, a high sensitivity of 3.617 kPa- 1, and excellent durability over 19 500 compression-release cycles. It also detects NH3 concentrations as low as 1 ppm with stable performance over 60 days. The dual-functional sensor enables complementary monitoring of mechanical physiological signals, including respiration, pulse, and body motion, together with metabolic information from exhaled NH3. A five-channel sensor array further decodes numerical gestures with 100% accuracy via machine learning and wireless communication. Integrating respiratory mechanical sensing with exhaled NH3 detection, this platform offers potential for longitudinal, noninvasive multiparametric monitoring, particularly for CKD assessment, human-machine interfaces, smart wearables, assistive technologies, and telemedicine.