Preparation and Antibacterial Properties of the Core-Shell Structure SiO_2@Ag Nanoparticles

摘要

The core-shell structure SiO_2@Ag nanoparticles were synthesized by a facile chemical reduction method. Firstly, the mercapto-silica spheres had been prepared by the stober method, in which 3-mercaptopropyltrimethoxysilane (MPS) was used as a sole silica source. The reaction involves mixing the MPS precursor, ammonia in aqueous solvent at room temperature. Secondly, the core-shell structure SiO_2@Ag nanoparticles were synthesized by reducing AgNO_3 on the surface of mercapto-silica spheres in the presence of the reducing agent. The core-shell structure SiO_2@Ag nanoparticles were investigated by means of ultraviolet-visible absorption spectroscopy (UV-vis), high resolution transmission electron microscopy (HRTEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Antibacterial properties of the as-synthesized SiO_2@Ag nanoparticles were investigated using both Gram negative of Escherichia coli (E.coli) and Gram positive of Staphylococcus aureus (S. aureus) as bacterial strains. The results show that the core-shell structure SiO_2@Ag nanoparticles exhibit excellent antibacterial properties against E. coli and S. aureus bacteria.