Studies on antimicrobial potential of doped ZnO nanoparticles

Abstract

newline ABSTRACT newlineThe present work reports the influence of doping on structural, optical, antimicrobial, newlinephotocatalytic, synergistic and toxic properties of zinc oxide nanoparticles (ZnO NPs). Iron newline(Fe), Manganese (Mn), Cobalt (Co) and Copper (Cu) were the different dopants introduced in newlineZnO nanoparticles with 1% and 10% doping concentration through simple chemical coprecipitation newlinetechnique. Polyvinylpyrrolidone (PVP) was used as capping agent for control newlinegrowth of nanoparticles. Structural, morphology and optical properties of synthesized newlinenanoparticles were measured using X-ray powder diffraction (XRD), transmission electron newlinemicroscope (TEM) and Fourier-transform infrared spectroscopy (FTIR). The antimicrobial newlineactivities of NPs were studied against fungi and bacteria (gram-positive bacteria and gramnegative newlinebacteria) using the standard disc diffusion method. The methylene blue (MB) was newlineemployed as organic pollutant for photocatalytic activities under UV light. The experimental newlineresults clearly demonstrate that ZnO nanoparticles doped with 10% Cu, Co, Fe and Mn newlineimpurities atoms exhibit more antimicrobial and photocatalytic activities as compared to 1% newlinedoped and undoped ZnO nanoparticles. The enhancement in antimicrobial effect and newlinephotocatalytic degradation is attributed to the generation of reactive oxygen species (ROS) newlinedue to the synergistic effects of Mn, Fe, Cu and Co loading. Effect of nanoparticles on the newlineultrastructure of microorganisms and to some extent the underlying mechanism for the newlineinactivation/killing of microorganisms was studied using scanning electron microscopy newline(SEM) and transmission electron microscopy (TEM). Results from SEM and TEM newlinedemonstrated that doped ZnO NPs changed the cell membrane components, including lipids newlineand proteins, although no significant morphological changes were observed. Also, doped newlineZnO NPs exhibited potent antifungal effects on fungus tested, probably through destruction newlineof membrane integrity. Toxicological studies revealed good homogeneity and purity of newlineundoped and doped ZnO nanoparticles. Toxological studies of undoped and doped ZnO newlinenanoparticles revealed their distribution to all of the organs investigated, with the highest newlinelevels being observed in the liver and kidney. Other than effect on liver and kidney weight newlineloss, hypoactivity, altered blood values were also observed. Experimental results suggest that newlinedoped ZnO NPs has considerable antimicrobial activity, and can be used as an effective newlineantimicrobial agent. However, further investigation for clinical applications is warranted.