Harnessing the power of Neobacillus niacini AUMC-B524 for silver oxide nanoparticle synthesis: optimization, characterization, and bioactivity exploration

Biotechnology provides a cost-effective way to produce nanomaterials such as silver oxide nanoparticles (Ag ONPs), which have emerged as versatile entities with diverse applications. This study investigated the ability of endophytic bacteria to biosynthesize Ag ONPs. A novel endophytic bacterial strain, Neobacillus niacini AUMC-B524, was isolated from Lycium shawii Roem. & Schult leaves and used to synthesize Ag ONPS extracellularly. Plackett-Burman design and response surface approach was carried out to optimize the biosynthesis of Ag ONPs (Bio-Ag ONPs). Comprehensive characterization techniques, including UV-vis spectral analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, dynamic light scattering analysis, Raman microscopy, and energy dispersive X-ray analysis, confirmed the precise composition of the Ag ONPS. Bio-Ag ONPs were effective against multidrug-resistant wound pathogens, with minimum inhibitory concentrations (1-25 µg mL ). Notably, Bio-Ag ONPs demonstrated no cytotoxic effects on human skin fibroblasts (HSF) in vitro, while effectively suppressing the proliferation of human epidermoid skin carcinoma (A-431) cells, inducing apoptosis and modulating the key apoptotic genes including Bcl-2 associated X protein (Bax), B-cell lymphoma 2 (Bcl-2), Caspase-3 (Cas-3), and guardian of the genome (P53). These findings highlight the therapeutic potential of Bio-Ag ONPs synthesized by endophytic N. niacini AUMC-B524, underscoring their antibacterial efficacy, anticancer activity, and biocompatibility, paving the way for novel therapeutic strategies.