Conductive hydrogel-based flexible pressure sensors: Sensing mechanisms and applications in foot pressure monitoring.
Abstract
Conductive hydrogels combine flexibility, biocompatibility, and electrical conductivity and are therefore promising materials for flexible pressure sensors. This review examines the application of conductive hydrogels to plantar pressure monitoring for foot disease management and gait analysis. Four major sensing mechanisms are examined, including piezoresistive, capacitive, piezoelectric, and triboelectric sensing. A comparison is made of their respective merits, limitations and suitable applications. Conductive hydrogels are broadly classified as ionically conductive, electronically conductive, or hybrid conductive types. The mechanical performance of conductive hydrogels can be enhanced through double-network architectures, nanocomposite reinforcement, and slide-ring topologies. Anti-freezing, anti-swelling, and self-healing designs can improve environmental stability and operational durability. Self-adhesion and antibacterial activity further broaden the range of potential applications. At the device and system levels, reliable operation depends on sensor array design, gait parameter extraction, and system integration. AI-assisted signal processing may further improve data interpretation and analytical accuracy. Applications include daily activity recognition, exercise monitoring, and the detection of flatfoot, neuropathy-related abnormalities, and diabetic foot ulcers. These capabilities enable continuous, noninvasive plantar pressure mapping and may facilitate earlier intervention. Despite recent advances, major barriers remain at the material, device, and clinical levels. Future development is expected to focus on multimodal sensing, self-powered operation, and closed-loop intervention. Overall, conductive hydrogel-based plantar pressure sensors hold considerable promise for foot health monitoring. Their translation into routine clinical practice will depend on close collaboration among materials scientists, engineers, and clinicians.