| Silver nanoparticles were prepared by dual-reduction method. hydroboration sodium (NaBH4) and Sodium citrate were both used as reducing agents. Take the hydroboration sodium as the first reductive agent, hydroboration sodium and sodium citrate was used as co-reducing agents. Amylum was used as stabilizer. The experimental conditions, such as concentration and reaction time, were studied in detail. The silver nanoparticles were characterized by transmission electron microscopy and UV-Vis absorption spectroscopy. A preliminary react ion mechanism was proposed after characterizing the samples, which were prepared under different conditions, by absorption spectroscopy. The effects of nanoparticles'morphology and structure on its antibacterial property were researched. To investigate the antibacterial mechanism of silver nanoparticles, the growth, morphology and ultrastructure of Escherichia coli and Staphylococcus aureus were analyzed. Results showed that obvious bacteriostasis effects could be observed when 400μL 0.2 mmol?L-1 Silver nanoparticles added into Escherichia coli solution (600/mL) above 37℃. Better bacteriostasis results could be obtained when more nanoparticles and longer time were available. Besides we found that nanoparticles are more capable of killing Staphylococcus aureus. Silver nanoparticles with smaller size and higher volume fraction showed higher antibacterial property. The research indicated that under the compound use of Silver nanoparticles and H2O2 or CTAB, its antibacterial property is higher than Silver nanoparticles.
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