In Situ Construction of Bacterial Dressing for Low-Temperature Sterilization in Infected Lesions

While photothermal sterilization offers significant advantages over antibiotics for treating surgical site infections, its application is limited by side effects caused by excessive heat. To address this dilemma, this study focuses on the often-overlooked factor of temperature inhomogeneity within irradiated regions, which impacts photothermal efficacy. We propose a solution termed "bacterial photothermal dressing". In this approach, tannic acid (TA) first attaches to bacteria or biofilm and subsequently captures surrounding FeIII ions to form a close-fitting FeIIITA dressing in situ. For comparison, a conventional photothermal sterilization method is established by directly administering FeIIITA nanoparticles to infected sites. The bacterial photothermal dressing approach allows for bacterial elimination at much lower temperatures, minimizing heat-related side effects. Moreover, the acidic microenvironment within the biofilm can trigger the gradual release of TA, permitting continuous antiseptic and anti-inflammatory effects. This sustained activity enhances antibacterial efficacy and helps prevent secondary infection following photothermal treatment. Consequently, this approach significantly accelerates wound healing by improving bactericidal efficiency and reducing inflammatory responses.