Antibacterial MoS₂/CaCO₃ Nanoplatform for Combined Photothermal, Photodynamic, and Nitric Oxide Therapy

Wound infections affect the health of nearly 300 million people worldwide, and biofilm formation is a major factor that contributes to their persistence. In this study, we designed a combined photothermal therapy (PTT)/photodynamic therapy (PDT)/nitric oxide (NO) antibacterial nanoplatform (MSC@CaCO3). First, photothermally responsive molybdenum disulfide (MoS2) nanospheres (90-110 nm) were prepared, then sodium nitroxide alginate (SANO) and dihydroporphyrin e6 (Ce6) were attached to allow the release of NO and reactive oxygen species (ROS) in response to illumination. While acid-sensitive calcium carbonate comes into contact with the microacidic environment of biofilm, it will crack and release drugs, and free Ca2+ can assist sodium alginate (SA) to promote wound healing. The results showed that the photothermal conversion efficiency of the nanoplatform was 48.9%. The bacterial inhibition rates of MSC@CaCO3 for multidrug-resistant (MDR) Escherichia coli (E. coli) and MDR Staphylococcus aureus (S. aureus) were both more than 96%. MSC@CaCO3 also showed effective inhibition for the growth of drug-resistant bacterial biofilm. A single-factor experiment was carried out to assess the bacterial inhibition efficiency by PTT or PDT. The mouse wound infection model recovered after 10 days of treatment by MSC@CaCO3 under illumination. The toxicity assay demonstrated that the nanoplatform had no significant toxicity. In conclusion, the prepared MSC@CaCO3 nanoplatform can effectively utilize the characteristics of the biofilm microenvironment to confer protection against drug-resistant bacterial infections and promote wound healing. This study provides a basic reference for the application of cost-effective and multifunctional nano-anti-infective drugs.