Bismuth Tungstate-Based\nNanoparticles Promoting Healing\nof Drug-Resistant Bacteria Infected Abscesses by Chemical/Low-Temperature\nPhotothermal Therapy

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