Preparation and characterization of core-shell structure of SiO2@Cu antibacterial agent.

A simple, low cost and convenient method was used to prepare SiO2@Cu core-shell composite using SiO2 spheres as the core and copper nanoparticles as the shell. A uniform spherical particle of SiO2 was fabricated according to an improved Stöber method. The SiO2 spheres served as a support for the immobilization of copper by reducing Cu2+ in aqueous solution using Fe power. The chemical structures and morphologies of the SiO2 and SiO2@Cu composite were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). E. coli (Escherichia coli), S. aureus (Staphylococcus aureus) and C. albicans (Candida albicans) were utilized to test its antibacterial effect. Results of XRD, TEM and XPS demonstrated that the copper nanoparticles shell supported on the surface of SiO2 spheres. With regard to the antibacterial effect, E. coli was more easily killed than S. aureus and C. albicans after 24 h incubation, and the pictures of TEM showed obviously morphological changes of the antibacterial activity. The results demonstrated that Cu supported on the surface of SiO2 spheres without aggregation, which was proved to be a good novel antibacterial material.