Synthesis of polystyrene@(silver-polypyrrole) core/shell nanocomposite microspheres and study on their antibacterial activities

We reported the synthesis of polystyrene@(silver-polypyrrole) (PS@(Ag-PPy)) nanocomposite microspheres with the well-defined core/shell structure, in which the functionalized PS microspheres by the sulfonic acid groups were employed as template. The diameter of the synthesized PS microsphere template and AgNP was 1.26 mu m and 50 nm, respectively. In order to well control the redox reaction between Ag+ and Py monomer and to avoid the accumulation of these AgNPs during synthesis process, the complexation of triethanolamine (TEA) and silver ion ([Ag(TEA)(2)](+)) was employed as the oxidant, so that the generation rate of AgNPs was in turn decreased. Moreover, compared with the redox reaction between AgNO3 and Py, the introduction of [ Ag(TEA)2](+) ions resulted in the improved coverage and distribution of AgNPs around the surface of PS microspheres. Meanwhile, the loading amount of Ag-PPy nanocomposites on the final microspheres was adjustable. The increasing concentrations of Py monomer and [Ag(TEA)(2)](+) ions resulted in the increase of Ag-PPy nanocomposite loading. The results of antibacterial experiment suggested that the synthesized PS@(Ag-PPy) composite microspheres showed the prominent antibacterial properties against both the Gram-negative bacteria of Escherichia coli and the Gram-positive bacteria of Staphylococcus aureus. For the bacteria with concentration at 1 x 10(5) - 9 x 10(5) cfu/mL, the microspheres can kill the bacteria above 3-log reduction with the concentration of PS@(Ag-PPy) composite microspheres at 50 mu g/mL, in which the weight fraction of Py in the composite microspheres was above 10 wt%. When the weight fraction of Py in the composite microspheres was at 5 wt%, the 2-log reduction of in bacterial viability could also be obtained. [GRAPHICS] .