One-step spray pyrolysis synthesis of ZnO/Ag hollow spheres for enhanced visible-light-driven antibacterial applications and wound healing

Abstract

ZnO/Ag hollow particles were synthesized via a one-step spray pyrolysis method for enhanced antibacterial activity and wound healing applications. The hollow structure and uniform distribution of Ag nanoparticles within the ZnO matrix were confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). UV-Vis spectroscopy and Tauc plot analysis revealed a reduction in the bandgap, attributed to the surface plasmon resonance (SPR) of Ag, improving light absorption in the visible range. Antibacterial tests against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA) showed that ZnO/Ag composites exhibited significantly enhanced antibacterial efficacy under visible light compared to pure ZnO. The antibacterial mechanism was investigated using electron paramagnetic resonance (EPR) spectroscopy, which confirmed the generation of reactive oxygen species (˙OH and ˙O₂⁻). These results indicate that ZnO/Ag hollow composites are promising candidates for antibacterial coatings and wound healing applications, especially under visible light activation.