Photothermal-photocatalytic synergistic sterilization by Ag2S/V2CTx@PDA nanocomposites under 808 nm near-infrared irradiation.

Given the limitations of traditional antimicrobial strategies and the pressing demand for efficient, biocompatible sterilization, photochemistry-mediated approaches have emerged as promising solutions, leveraging light-matter interactions for targeted pathogen elimination. In this study, A nanocomposite was engineered through the integration of the excellent near-infrared (NIR) photothermal properties of MXene (V₂CTx) with biocompatible Ag2S nanoparticles. Subsequent to this, surface modification with polydopamine (PDA) was carried out via self-polymerization. The abundant functional groups of PDA not only enhanced biocompatibility but also amplified NIR photothermal conversion, synergizing with the intrinsic photothermal activity of V₂CTx. The Ag2S/V2CTx@PDA nanocomposite demonstrated dual functionality under 808 nm NIR light, efficiently converting photon energy into heat (reaching a temperature of 50.2 °C) and generating photocatalytic reactive oxygen species (ROS). Experimental results revealed an exceptional sterilization efficiency of 99.99% against Staphylococcus aureus (S. aureus) within 25 min of irradiation at a power density of 0.74 W/cm2 using the optimal Ag2S-30%/V2CTx@PDA composite. This high-performance antibacterial effect is attributed to the synergistic combination of photothermal conversion and photocatalytic ROS generation, providing a rapid antibacterial strategy.