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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. [ABSTRACT FROM AUTHOR]

Drug-resistant bacterial infections pose a significant threat to global public health. Furthermore, the formation of biofilms makes traditional antibiotic treatments significantly less effective in killing multidrug-resistant (MDR) bacteria. In this work, we prepared a molybdenum disulfide (MoS2) nanosphere-based nanocomposite that utilized both photothermal therapy (PTT) and chemodynamic therapy (CDT) for effectively eradicating biofilms. A layer of manganese dioxide (MnO2) was adsorbed onto the surface of the MoS2 nanospheres by redox and electrostatic adsorption methods, and the resulting MoS2/MnO2 were loaded with 2,2′-azobis-[2-(2-imidazolin-2-yl)-propane]-dihydrochloride (AIPH) to form the MoS2/MnO2-AIPH nanocomposite (MMA). The microenvironment of biofilms is slightly acidic, lacks oxygen, and has a high concentration of glutathione (GSH). The MnO2 was capable of reacting with GSH to deplete it while also generating •OH radicals for CDT. In the presence of NIR light (808 nm), the temperature increase brought about by PTT further enhanced the CDT efficacy synergistically. The results showed that the photothermal conversion efficiency of the MMA was 40.5% at a concentration of 100 μg/mL, and the biofilm eradication rate of both MDR Escherichia coli and MDR Staphylococcus aureus was above 90%. The high bacterial inhibition rate (above 96%), as well as the excellent biosafety and biocompatibility of the MMA nanocomposite enabled it to effectively promote wound healing, which has significant implications in treating bacterial infections and promoting wound healing in clinical settings. [ABSTRACT FROM AUTHOR]

Drug-resistant bacterial infections pose a serious threat to human public health. Biofilm formation is one of the main factors contributing to the development of bacterial resistance, characterized by a hypoxic and microacidic microenvironment. Traditional antibiotic treatments have been ineffective against multidrug-resistant (MDR) bacteria. Novel monotherapies have had little success. On the basis of the photothermal effect, molybdenum disulfide (MoS 2 ) nanoparticles were used to link quaternized polyethylenimine (QPEI), dihydroporphyrin e6 (Ce6), and Panax notoginseng saponins (PNS) in a zeolitic imidazolate framework-8 (ZIF-8). A multifunctional nanoplatform (MQCP@ZIF-8) was constructed with dual response to pH and near-infrared light (NIR), which resulted in synergistic photothermal and photodynamic antibacterial effects. The nanoplatform exhibited a photothermal conversion efficiency of 56%. It inhibited MDR Escherichia coli ( E. coli ) and MDR Staphylococcus aureus ( S. aureus ) by more than 95% and effectively promoted wound healing in mice infected with MDR S. aureus . The nanoplatform induced the death of MDR bacteria by promoting biofilm ablation, disrupting bacterial cell membranes and intracellular DNA, and interfering with intracellular material and energy metabolism. In this study, a multifunctional nanoplatform with good antibacterial effect was developed. The molecular mechanisms of MDR bacteria were also elucidated for possible clinical application.