Preparation of polyvinyl alcohol (PVA) aerogel microsphere loaded with biogenic zinc oxide nanoparticles as potential antibacterial drug

With the rise of resistance to antimicrobial agents and infections primarily caused by multidrug-resistant (MDR) bacterial strains, researches have been actively striving to create alternative therapeutic materials and enhance drug delivery approaches. In this context, we introduce ZnO NPs/PVA aerogel microsphere as a novel bactericidal agent against MDR bacteria. To prepare the ZnO NPs, Camellia sinensis (C. sinensis) leaf extract was employed in the biosynthesis method as a reducing and capping agent. The resulting biogenic ZnO NPs were incorporated with PVA solution to prepare the ZnO NPs/PVA aerogel microsphere by the sol-gel approach and freeze-dry cycle. ZnO NPs and ZnO NPs/PVA aerogel microsphere were characterized using UV-vis, FTIR, XRD and SEM techniques. Importantly, the ZnO NPs and ZnO NPs/PVA aerogel microsphere demonstrated strong antibacterial activity against MDR bacteria. As indicated by agar diffusion assay, the incorporation of ZnO NPs with PVA in aerogel composite enhances their antibacterial activity. Additionally, the antibacterial effectiveness of ZnO NPs was confirmed by their MBC values of 6.25, 12.5 and 12.5 U/ml as well the MIC values of 12.5, 12.5 and 12.5 U/ml against K. pneumonia, P. aeruginosa and E. coli, respectively. Furthermore, the optical density measurement of bacterial growth indicated that ZnO NPs/PVA aerogel microsphere inhibit the growth of all MDR bacterial species. The combination between ZnO NPs and certain antibiotics enhanced their effect against MDR bacterial strains. Our results highlight the effectiveness of ZnO NPs/PVA aerogel microsphere as a promising and potential antibacterial drug to combat pathogenic MDR bacteria.