A highly stretchable, self-adhesive, antimicrobial conductive hydrogel with guar gum/acrylic acid/MXene@AgNPs for multifunctional wearable sensors and electromagnetic interference shielding

Multifunctional conductive hydrogels have attracted extensive attention in the fields of biomedicine and health monitoring. However, integrating excellent stretchability, self-adhesion, sensitive sensing, electromagnetic interference (EMI) shielding, and antibacterial properties into conductive hydrogels for wearable sensor applications remains a significant challenge. In this study, a multifunctional conductive hydrogel (GAMA) was prepared by incorporating MXene@Ag nanoparticles (AgNPs) as conductive fillers, which were uniformly dispersed within a dual-network structure of guar gum/acrylic acid. Serving as conductive agents, reinforcing fillers, and antibacterial components, MXene@AgNPs enable the GAMA hydrogel to achieve multifunctional integration and balanced performance. The GAMA hydrogel exhibits outstanding mechanical performance with a tensile strength of 97 kPa and elongation at a break of 850%, self-adhesion (21.5 kPa), and high conductivity (14.04 mS cm^-1). Additionally, we employed this hydrogel as a flexible strain sensor to monitor human motion, achieving high sensitivity (gauge factor (GF) of 6.48 at 300% strain). The <i>in situ</i> synthesis of AgNPs on MXene nanosheets enhances polarization and interfacial losses of electromagnetic waves, endowing the hydrogel with an EMI shielding effectiveness of 34.5 dB. Furthermore, comprehensive biocompatibility evaluations confirm its excellent antibacterial performance, hemocompatibility, and cytocompatibility. Therefore, these properties endow the multifunctional GAMA hydrogel with great potential for applications in wearable sensors for human motion monitoring and EMI shielding.