Synthesis of silver-titanium dioxide nanocomposites for antimicrobial applications

摘要

Silver-titanium dioxide (Ag-TiO_2) nanostructures have attracted increasing attention because of unique functional properties and potential applications in many areas such as photocatalysis, antibacterial, and self-cleaning coatings. In this study, Ag@TiO_2 core– shell nanostructures and Ag-decorated TiO_2 particles (TiO_2@Ag) (the size of these two nanoparticles is ranging from 200–300 nm) have been synthesized by a developed facile but efficient method. These two types of hybrid nanostructures, characterized by various advanced techniques (TEM, XRD, BET and others), exhibit unique functional properties particularly in antibacterial toward Gramnegative Escherichia coli, as a case study. Specifically: (i) the TiO_2@Ag nanoparticles are superior in bacterial growth inhibition in standard culture conditions (37 ℃ incubator) to the Ag@TiO_2 core–shell ones, in which silver may dominate the antibacterial performance; (ii) while after UV irradiation treatment, the Ag@TiO_2 core–shell nanoparticles exhibit better performance in killing grown bacteria than the TiO_2@Ag ones, probably because of theAg cores facilitating charge separation for TiO_2, and thus produce more hydroxyl radicals on the surface of the TiO_2 particles; and (iii)withoutUVirradiation, both TiO_2@Ag and Ag@TiO_2 nanostructures show poor capabilities in killing mature bacteria. These findings would be useful for designing hybrid metal oxide nanocomposites with desirable functionalities in bioapplications in terms of sterilization, deodorization, and water purification.