Objective To observe inhibitory effect of silver cluster assemblies capped by D-penicillamine on Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus).
Methods The structure of D-penicillamine stabilized silver cluster assemblies was examined with infrared spectroscopy, X-ray photoelectron spectroscopy and Auger electron spectroscopy. Then, the E.coli and S.aureus strains were cultivated with various doses of D-penicillamine stabilized silver cluster assemblies. Scanning electron microscope was used to observe the proliferation of the cultivated bacteria.
Results The minimum inhibitory concentration (MIC) and the half maximal inhibitory concentration of silver cluster assemblies for E. coli were 1 μg/mL and 0.86 μg/mL; no inhibition effect of silver cluster assemblies on S.aureus at the concentration of 200 times higher than the MIC for E. coli. Observations with scanning electron microscope revealed obvious rupture of the cell membranes of E. coli cultivated with silver cluster assemblies, which may be contributed to the bacterial death.
Conclusion Silver cluster assemblies has obvious inhibition effect on E. coli but no such effect on S.aureus.
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