Abstract: Abstract: Objective To investigate the effect of graphene oxide-silver nanocomposites（GO-Ag）on Streptococcus mutans（S.mutans）and its biofilm formation. Methods Colony forming units counting method, flow cytometry and live/dead staining method were used to detect the antibacterial effect of graphene oxide-silver nanocomposites on S.mutans. The biomass of GO-Ag-treated S.mutans biofilm was tested by crystal violet assay. The data were analyzed by One-Way ANOVA and Dunnett’s test. Results The results of antibacterial effect of GO-Ag tested by all these methods had significant difference with the control group（P<0.05）. Comparing with the control group, the biomass of GO-Ag-treated S.mutans biofilm was greatly reduced（P<0.05）. Conclusion Graphene oxide- silver nanocomposites（GO-Ag）exhibited great antibacterial effect and biofilm inhibition on S.mutans.

Key words: graphene oxide, silver nanoparticles, Streptococcus mutans, antibacterial property