MXene/Carbon Dot Nanocomposites with Photothermal/Physical Synergistic Antibacterial Capability for Wound Healing

Bacterial infections and excessive inflammatory responses pose critical challenges to effective wound healing. To address these issues, we developed a multifunctional nanocomposite, Ti3C2Tx-US-CDs, by integrating ultrasonically exfoliated Ti3C2Tx (Ti3C2Tx-US) with amine-functionalized carbon dots (CDs) through a simple postfunctionalization approach. This nanocomposite combines the high specific surface area of Ti3C2Tx with the abundant surface functional groups of CDs, resulting in high antioxidant reactivity, antibacterial performance, and photothermal stability. Under near-infrared (NIR) irradiation, the composite exhibits remarkable physicochemical synergistic antibacterial activity, effectively eradicating Escherichia coli and Staphylococcus aureus. Ti3C2Tx-US-CDs display a dual-modal antibacterial mechanism: the positively charged CDs disrupt bacterial membranes via electrostatic interactions, while Ti3C2Tx-US exerts potent antibacterial effects through photothermal activity and the physical cutting action of its nanoscale sharp edges. Ultraviolet photoelectron spectroscopy (UPS) characterization reveals that the synergistic effects of charge separation and recombination at the Ti3C2Tx-US/CDs interface significantly enhance energy and electron exchange, leading to enhanced reactive oxygen species (ROS) scavenging ability via redox activity. In vivo experiments using S. aureus-infected skin wound models demonstrate that Ti3C2Tx-US-CDs significantly accelerate wound healing under NIR irradiation by suppressing bacterial infection, promoting angiogenesis, and facilitating tissue regeneration. This study demonstrates the potential of Ti3C2Tx-US-CDs as a next-generation nanomaterial for advanced wound management and offers a promising therapeutic strategy for combating bacterial infections and inflammation.