Study On Doping And Antimicrobial Effect Of Semiconductive Metallic Oxides

In this paper, research progresses on the inorganic antimicrobial materials have been compared and reviewed. The nano-sized TiO₂ was doped with V, Mn and Zn, respectively, by solid-solution process, and the tetra-pod like zinc oxide whisker (T-ZnO) was also doped with silver by solid-solution method. The affects of doping on the crystal structure and antimicrobial effects of the samples were investigated by TEM, XRD, STM, UV-vis spectra and MIC tests.The nano-sized TiO₂ was doped with V, Mn, Zn, and co-doping of V and Ag by solid-solution process. The antimicrobial activities of the samples were evaluated by test of MIC values for typical microbes such as Escherichia coli and Staphylococcus aureus under natural night condition, and the influences of doping on the structure and optical behaviours were discussed. The results indicated that dopant of vanadium, manganese and zinc with 1 at.% could be loaded in the octahedral lattice of TiO₂, and no second phase formed. Obvious red-shift was observed in the UV-vis reflection spectra in vanadium doped TiO₂ nanoparticles, and vanadium doping was helpful to enhance the antibacterial activity of TiO₂, while there was no obvious effect for magnesium or zinc doping. The antibacterial activity of nano-sized TiO₂ co-doped with silver and vanadium has been enhanced distinctively, much better than those of the samples doped with sole element. Further investigation showed that the higher the silver loaded in the co-doped TiO₂, the better effect for the antimicrobes behaves.The silver doped T-ZnO samples were also prepared by solid-solution process at 900℃. The influences of doping on the morphology, the crystalline structure, the optical properties and the antimicrobial effects were studied byXRD, SEM and MIC evaluation. The results demonstrated that silver could not entirely load into the lattice of wurzite phase of ZnO when the doping concentration of silver was 1 at.%, and there might exist second phase of silver (simple substrance) in the samples. It was also observed that the higher the calcinating temperature was, the more the silver ion loaded into the lattice of ZnO. There was no second phase of silver in the T-ZnO sample doped with 0.1 at.%, and the Ag+ might totally loaded into the lattice of wurzite, as a result, the lattice parameters of the wurzite increased. The results of MIC evaluations indicated that the antimicrobial activity of T-ZnO was highly enhanced by doping with silver.