Enhanced anti-Escherichia coliproperties of Fe-doping in MgO nanoparticles

Hetero-elements doping is an effective way to modify the composition and nanostructure of metal oxides. These modifications could lead to changes in physical and chemical properties correspondingly. In this study, Fe-doped MgO nanoparticles (NPs) were synthesized by simple calcination method in air. The antibacterial activity of MgO NPs against Escherichia coli (E. coli, ATCC 25922) was significantly improved as shown by the bactericidal efficacy test results. According to X-ray diffraction (XRD) results, Fe was successfully doped into MgO lattice and mainly adopted interstitial doping. The Fe-doping led to increased oxygen vacancies and OA content (from 13.5% to 41.3%) on MgO surface, which may have facilitated the reactive oxygen species (ROS) generation and bacteria death. The wrinkled and sunken E. coli surface after contact with Fe-doped MgO NPs also confirmed the existence of adsorption damage mechanism. Thus, the antibacterial activity enhancement against E. coli was originated from the synergistic effect of increased ROS concentration and the interaction with Fe-doped MgO NPs.