Synthesis and Modification of Zinc Oxide Nanoparticles for Antimicrobial Activities and UV light Protection

Abstract

In this research the effects of temperature and polyvinyl Alcohol (PVA) concentrations on the structural and optical properties of zinc oxide nanoparticles were investigated using a simple and cost effective sol-gel method. The XRD and SEM images of ZnO NPs indicated increment in the particle size as temperature and PVA concentration increased. Also the antimicrobial activity of zinc oxide (ZnO) nanoparticles (NPs) synthesized by different chemical, thermal and green routes were systematically investigated with an aim to determine which method yields the most efficient antimicrobial property. The experimental results showed that the antimicrobial activity of ZnO NPs increased with decreasing size of the crystal. Interestingly, the antimicrobial activity of ZnO NPs synthesized using green route was more effective than the chemical or thermal route. The binding of ZnO NPs with caffeic acid (CFA) were also investigated by fluorescence quenching, UV Vis, FTIR, TEM and DLS under human physiological conditions. The study results indicated the fluorescence quenching between ZnO NPs and CFA were rationalized in terms of static quenching mechanism or the formation of non fluorescent CFA ZnO. From fluorescence quenching spectral analysis the quenching constant (ksv), quenching rate constant (kq), binding constant (Ka), number of binding site (n), thermodynamic properties, and conformational changes of the interaction were determined. ZnO NPs were synthesized at different temperatures and reaction media of water (S-1) and 1, 2-ethanediol (S-2) using precipitation and in situ methods on the surface of cotton fabric for UV light protection. The UV protection ability of ZnO NPs coated on textiles was investigated using UV-Vis spectroscopy by measuring the ultraviolet protection factor (UPF) in the ranges of 280-400 nm. Higher values of UPF were obtained for ZnO NPs prepared using an in situ method. The UPF value obtained by this method was found to be 320 which demonstrate its excellent ability to block UV radiation.