Quercetin-Enhanced Interfacially Dynamically Bonded Hydrogels with Fast Self-Healing and Ultrahigh Strain Sensitivity for Wearable Human Health Monitoring

Conductive hydrogels with multifunctional properties have been increasingly recognized as ideal materials for wearable sensing applications, yet balancing high sensitivity, mechanical properties, and self-healing remains a critical scientific challenge. Herein, a PAA/PEI/Que/Al³⁺ hydrogel was synthesized via a multidynamic network strategy. The hydrogel demonstrated remarkable tensile strength (93.2 kPa) and ultrahigh sensitivity (Gauge Factor = 22.09), capable of detecting motions ranging from joint movements to subtle physiological signals (pulse, speech). The introduction of quercetin could introduce catechol-mediated self-adhesion and enhance the self-healing capability of the hydrogels. With synergistic contributions from dynamic imine bonds, hydrogen bonding, metal coordination, and electrostatic interactions, the hydrogel demonstrated 100% self-healing efficiency within 2 h without external stimulation. Notably, the self-healed hydrogel retained postrepair functionality with the accurate monitoring of human movements, demonstrating exceptional durability for long-term wearable applications. This breakthrough addresses persistent durability challenges in flexible electronics while establishing a quercetin-enhanced dynamic bonding system that opens frontiers in personalized healthcare monitoring systems and human-machine interfaces.