Preparation Of Hollow Mesoporous Silver-loaded Silica Microspheres And Their Antibacterial Property

The spread of germs menace the health of mankind seriously, to sterilize and inhibit the propagation of bacterial by antibacterial materials is an important way to improve the health level of people. Nano silver antibacterial materials have many advantages such as strong antibacterial activity, broad antibacterial spectrum, high security and so on. The preparation of silver nanoparticles based on antibacterial composites is a hot topic recently. However, silver nanoparticles have tendancy to aggregate due to their high surface activity, and the rate of silver release form nano silver-doped antibacterial composite materials is too fast, wihich would affect their antibacterial performance and chemically antibacterial durability. Aiming at solving these problems, we worked out an reaserch on hollow mesoporous silver-loaded silica microspheres in this paper, the main contents are as follows:(1)We optimized the fabrication process of hollow mesoporous silica microspheres. In our research, monodisperse hollow mesoporous silica microspheres with diameter of ca.3μm and regual spherical morphology were fabricated by combining template method with Stober method, it was also conventient to control the structure and pore size of the microspheres.(2) A novel technology for synthesis of hollow mesoporous silver-loaded silica microspheres was proposed. First of all, Ag+ions were adsorbed on the surface of monodisperse sulfonated polystyrene(PS) beads via electrostatic interaction, and then reduced and stabilized by PVP to obtain PS/Ag composite spheres; after that, silica colloids generated by the hydrolysis and polymerization of tetraethoxysilane (TEOS) were assembled on the PS/Ag composite spheres via hydrogen bond forces to form a silica shell; lastly, the PS core and PVP were removed through calcination process, forming silver-doped hollow mesoporous silica composite microspheres.(3)The antibacterial properties of hollow mesoporous silver-loaded silica microspheres were investigated. This unique and innovative structure can protect the inner Ag nanoparticles and effectively avoid the aggregation problem existing in the traditional Ag colloid system, keeping the inherent activity of individual Ag nanoparticles. Meanwhile, owing to the mesoporous structure ofthe shell, Ag+ions could be slowly released from the interior of the shell, bringing out their durable antibacterial activity, and entending their service life. The research results indicated that:Ag nanoparticles, with the form of elementary substance, dispersedly loaded onto the interior wall of silica shell, and the shell was composed of a single layer of interconnected silica particles and mesopores; the antibacterial activity against Escherichia coli(E. coli) of samples with silver content of44.67wt%reached up to99.95%; they had favourable slow-release property, could lengthen release time obviously; and more importantly, could maintain a high level for long periods, the antibacterial activity against Escherichia coli(E. coli) of samples with silver content of44.67wt%exceeded95%after soaking into water for6months.