The Effect Of Nanometer Silver Base Inorganic Antimicrobial Agent(NSBIAA) On Candida Albicans Biofilm Formation

Objective:This study aimed to detect the effect of nanometer silver base inorganic antimicrobial agent (NSBIAA) suspension on Candida albicans biofilm formation and investigate the effective concentration of NSBIAA suspension to inhibit C. albicans biofilm formation. Evaluating the effect of the base resin (polymethylmethacrylate, PMMA) containing NSBIAA on C. albicans preliminary adhesion and biofilm formation, and identifying the proportion of NSBIAA in PMMA that can inhibit C. albicans preliminary adhesion and biofilm formation is another purpose of the study. These subjects were studied in order to provide experimental basis for improving the antibacterial properties of PMMA that can inhibit C. albicans biofilm formation.Methods:1.Prepared C.albicans suspension (106cell/ml) and NSBIAA suspension (10mg/ml,5mg/ml,2.5mg/ml,1.25mg/ml,0.625mg/ml,0.312mg/ml,0.156mg/ml,0.078mg/ml,0.039mg/ml,0.019mg/ml). C. albicans were cultured in NSBIAA suspension for12hours. And XTT reduction assay, crystal violet biofilm assay were applied to determine the metabolic activity and biomass of C. albicans biofilm. The biofilm was stained by crystal violet for observing its morphology.2.NSBIAA was incorporated in PMMA denture base powder through ball-grinding method. The PMMA specimens containing0%,1%,2%,3%,5%(V/V) were manufactured by applying stainless steel mold and squeezing polymerization integrated machine, each goup of four specimens. C. albicans biofilm mode were constructed on PMMA specimens in12-well plates. The fluorescence probe and confocal laser scanning microscopy (CLSM) were applied for observing C. albicans preliminary adhesion and biofilm.Results: 1.With the increasing of NSBIAA suspension concentration, the metabolic activity and biomass of C. albicans is reducing, the biofilm was damaged. The metabolic activity and biomass of the biofilm that in0.62mg/ml NSBIAA suspension was reduced by (96.1±3.0)%and (95.4+2.7)%respectively. And the morphology of C. albicans were not displayed under inverted microscope.2. There was no significant difference in Green Fluorescence Area (GFA), Total Fluorescence Area (TFA) and viable cell percentage among C.albicans preliminary adhered to PMMA containing0%,1%,2%,3%NSBIAA. The GFA, TFA and viable cell percentage of C. albicnas mentioned above were exceed5×104,5.5×104and95%respectively. GFA, TFA and viable cell percentage of C. albicnas adhered to the specimens containing5%NSBIAA were (3.43±0.24)×104,(4.07±0.33)×104and (82.37±5.84)%. The data were significant different from the data of the specimens with other incorporation percentage of NSBIAA.3.With the increasing of NSBIAA incorporation percentage in PMMA specimens,the germ tube generation rate of C. albicans preliminary adhered and the depth and the viable cell percentage of biofilm cultured72h were decreasing.The germ tube generation rate of C. albicans preliminary adhered on PMMA specimens containing3%,5%NSBIAA showed statistical difference with that of C. Albicans preliminary adhered on PMMA specimens containing0%,1%,2%NSBIAA, which was(60.26±5.6)%.The depth of biofilm formed on PMMA specimens containing5%NSBIAA was significant different from the depth of biofilm formed on the PMMA specimens containing0%,1%,2%,3%NSBIAA, which was (6.10±2.23)μm. The viable cell percentage of inner, intermediate and outer biofilm layer formed on PMMA specimens containing3%NSBIAA showed significant difference from that of the same biofilm layer formed on specimens containing0%,1%,2%NSBIAA. There was not C. albicans biofim formed on PMMA specimens containing5%NSBIAA through observing by CLSM.Conclusion:1.The NSBIAA suspension can inhibit C. albicans biofilm formation.The biofilm can not form in the0.62mg/ml NSBIAA suspension.2.The PMMA specimens containing NSBIAA can not inhibit C. albicans preliminary adhesion.3.The PMMA specimens containing NSBIAA can inhibit C.albicans biofilm formation. The biofilm can not form on PMMA specimens containing5%NSBIAA.