Multifunctional TA-CuS NPs-based conductive hydrogel with antibacterial capability for wearable real-time human motion sensor

Hydrogel-based flexible sensors have attracted significant attention in the fields of motion sensing. However, the construction of hydrogel substrate with long-term stability for humid and sweating conditions sensing still remains challenging. Herein, tannic acid-modified copper sulfide nanoparticles (TA-CuS NPs)-based multifunctional hydrogel with excellent adhesion, mechanical strength, swelling ability and antibacterial properties was developed as wearable sensor for sensitive and durable motion monitoring in moist environments. The hydrogel, containing abundant phenolic hydroxyl groups, allows dynamic cross-linking with sodium alginate (SA) and polyacrylamide (PAM), improving tensile strain to 1590 % and adhesion strength to 32 kPa. Meanwhile, its electrical conductivity increased from 0.02403 S·m −1 to 0.11432 S·m −1 , attributed to the formation of conductive pathways and interfacial interactions between TA-CuS NPs and polymer chains. Additionally, the incorporation of ions and hydrophilic functional groups within the hydrogel imparts superior swelling behavior and ionic conductivity, which facilitates sweat adsorption and stable signal transmission. Further, the peroxidase-like (POD)-like activity of TA-CuS NPs-based hydrogel promotes the generation of hydroxyl radicals (·OH), effectively inhibiting the growth of both Staphylococcus aureus (88.0 %) and Escherichia coli (93.8 %) within 24 h. As a result, this multifunctional flexible hydrogel-based sensor, endowed with sweat management and antibacterial capability can achieve the real-time and reliable human motion monitoring in wet scenarios with the working range of 0–500 %, and can further combine with designed integrated circuit and Bluetooth for wireless signals output. This designed wireless system allows for the recognition of various motions and provides early warnings of harmful motions, demonstrating the potential for practical application in the field of wearable sensing.