Mussel-inspired breathable and antibacterial strain sensors based on polyurethane fibrous membrane for human motion monitoring, human-machine interaction, and acupoint photothermal therapy

Flexible wearable strain sensors hold promising potential for applications in fields such as electronic skin, human health monitoring, and human-machine interaction. However, achieving a low detection limit, wide sensing range, and comfortable wearability simultaneously remains a challenge. In this study, a dual conductive layer consisting of silver nanoparticles (AgNPs) and carbon nanotubes (CNTs) was constructed on the surface of an electrospun porous polyurethane (PU) fibrous membrane via a mussel-inspired adhesion mechanism. The resulting PU membrane-based strain sensor demonstrated a low detection limit of 0.1%, a wide strain sensing range from 0 to 687%, and excellent durability over 6000 cycles. These features enabled the strain sensor to be successfully applied for whole-body human motion monitoring, including the detection of both subtle physiological signals and larger joint movements, as well as for human-machine interaction. Additionally, the high conductivity and synergy effect between AgNPs and CNTs endowed the sensor with efficient photothermal conversion capabilities, facilitating its use in photothermal therapy for traditional Chinese acupuncture points. The porous structure of the PU membrane, combined with the antibacterial properties of AgNPs, provided breathability and antibacterial functionality, enhancing the wearer comfort of the sensor. Consequently, the multifunctional wearable strain sensor demonstrates significant potential for applications in smart wearable electronics.