Bismuth Tungstate-Based Nanoparticles Promoting Healing of Drug-Resistant Bacteria Infected Abscesses by Chemical/Low-Temperature Photothermal Therapy

The development of traditional small molecule antibiotics is becoming increasingly challenging, and they are no longer effective against the growing number of multidrug-resistant infections. Therefore, in this study, polyhexamethylene biguanide–bismuth tungstate–poly(vinylpyrrolidone) nanoparticles (PHMB–BWO–PVP NPs) were synthesized to achieve effective treatment of drug-resistant bacterial infections through the synergistic chemical/low-temperature photothermal therapy (CT/LT-PTT). PHMB was loaded on BWO–PVP NPs via electrostatic interactions to form PHMB–BWO–PVP NPs that were stable in saline, phosphate-buffered saline, and Dulbecco’s modified Eagle’s medium. The NPs had a zeta potential of +10.6 mV and a particle size of about 45 nm. Moreover, the NPs were endowed with photothermal conversion ability by BWO and chemical antimicrobial capacity by PHMB. Thus, under LT-PTT, the NPs accelerated the release of PHMB, which exhibited excellent bactericidal effects against methicillin-resistant Staphylococcus aureus and drug-resistant Escherichia coli through synergistic effects, and inhibited the formation of bacterial biofilms. Importantly, PHMB–BWO–PVP NPs can eliminate skin abscesses in mice infected with drug-resistant bacteria via synergistic CT/LT-PTT, induce the transformation of M1 macrophages to M2 macrophages, promote collagen deposition and angiogenesis, and ultimately facilitate wound tissue healing.