Investigation of fuel type on the microstructure and antibacterial activity of Li-doped MgO nanoparticles.

MgO nanomaterial (nano-MgO) is a promising candidate in the antibacterial field owing to its high stability, environmental/ecological safety, good biocompatibility, and broad-spectrum antibacterial activity. However, the practical application of MgO nanoparticles is primarily limited by their relatively low antibacterial activity. In the present work, the fabrication of lithium (Li)-doped magnesium oxide (MgO) nanoparticles via a simple, low-cost solution combustion method is reported, and the effect of fuel type of citric acid, urea, and glycine as fuels on the microstructure and antibacterial properties of Li-doped MgO nanoparticles is systematically investigated. X-ray diffraction (XRD) analysis demonstrates that the Li-doped MgO has a cubic structure. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses reveal that the Li-doped MgO synthesized using citric acid as the fuel exhibits a uniformly distributed spherical morphology along with the smallest crystallite size (ca. 17.4 nm). In addition, the antibacterial effects of the Li-doped MgO nanoparticles against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are evaluated by using a bacterial killing/colony forming unit (CFU) assay. The results demonstrate that the antimicrobial activity of the Li-doped MgO varies according to the synthesis fuel, with the citric acid fuel inducing the best antimicrobial activity. The antibacterial mechanisms of the Li-doped MgO nanoparticles are also characterized. [ABSTRACT FROM AUTHOR]