Sustainable bioactivity enhancement of ZnO–Ag nanoparticles in antimicrobial, antibiofilm, lung cancer, and photocatalytic applications

Abstract

Cancer, microbial infections, and water pollution are significant challenges the modern human population faces. Traditional treatments for cancer and infections often have adverse effects and ecological consequences, while chemical methods for water decontamination can produce harmful byproducts. Metal nanoparticles, particularly zinc oxide (ZnO) and silver (Ag) nanoparticles, show promise in addressing these issues. However, doping Ag on ZnO NPs may synergistically enhance biomedical and therapeutic effects with fewer adverse consequences and improved photocatalytic properties for wastewater treatment. This study aimed to create ZnO and ZnO–Ag nanoparticles through green synthesis and compare their anticancer, antimicrobial, and photocatalytic activity mechanisms. XRD studies determined the crystal diameters of ZnO NPs and ZnO–Ag NPs to be 12.8 nm and 15.7 nm, respectively, with a hexagonal wurtzite structure. The XPS and EDS analyses confirmed the presence of Ag on the ZnO NPs. ZnO NPs and ZnO–Ag NPs exhibited low aggregation in aqueous suspensions, with zeta potentials of −20.5 mV and −22.7 mV, respectively. Evaluating antimicrobial and antibiofilm activity demonstrates that ZnO–Ag NPs have superior potential to ZnO NPs and standard antibiotic drugs against E. coli, S. typhi, B. subtilis, S. aureus, C. albicans, and A. niger. The results of the in vitro cytotoxicity test indicated that on the NCI-H460 lung cancer cell line, ZnO NPs and ZnO–Ag NPs demonstrated IC₅₀ values of 40 μg mL⁻¹ and 30 μg mL⁻¹, respectively. The photocatalytic degradation of methylene blue under direct sunlight revealed that ZnO and ZnO–Ag NPs degraded MB by 98% and 70% in 105 min, respectively. These results show that these nanomaterials may have great potential for treating the aforementioned issues.