Effect Of Silver Nanopartical On The Staphylococcus Epidermidis Biofilm

PART I EFFECT OF SILVER NANOPARTICAL ON THE STRUCTURE OF STAPHYLOCOCCUS EPIDERMIDIS BIOFILMObjective: To analyze the effect of silver nanoparticle on the structure of Staphylococcus epidermidis biofilm.Methods: The ethylene-vinyl acetate (EVA) plastics in different concentration of silver nanoparticle were used as carriers for the bacteria adhesion. The Staphylococcus epidermidis BF model in vitro was built by shaking method. The specimens were cultured for 2d and then respectively examined by Scanning Electron Microscope(SEM) and by the fluorescence microscope after being stained by FITC conjugated concanavalin A(FITC-conA).The 1d, 2d biofilm was monitored by Confocal Laser Scanning Microscope (CLSM). Quantification of the effect was calculated by Image Structure Analyzer (ISA) software. Results: After adding Silver nanopartical, the 2d biofilm was thin and abnormal compared with the control by SEM detection. The extracellular polymeric substances (EPS)in biofilm were significantly decreased after intervention with silver nanopartical which was visualized by the fluorescence The quantitative data from ISA software showed that the control and the 0.1% of silver nanopartical ,the thickness,average diffusion distance (ADD) and textual entropy(TE) was 17.55±2.08 and 10.80±1.68;3.56±0.54 and 1.85±0.06;5.29±0.57 and 2.72±0.39(p<0.05), Areal porosity (AP) was 0.90±0.02 and 0.98±0.01 (p<0.05). 0.05% of silver nanopartical have not the obvious effect compared with the 0.1% of silver nanopartical. The 1d biofilm showed the same tendency.Conclusion: The structure of Staphylococcus epidermidis biofilm can be destroyed by silver nanoparticle and high concentration has the better effect than low concentration.PAIHⅡEFFECT OF SILVER NANOPARTICAL ON THE GROWTH KINETICS OF STAPHYLOCOCCUS EPIDERMIDIS BIOFILMObjective: To analyze the effect of silver nanopartical on the growth kinetics of Staphylococcus epidermidis biofilmMethods: The ethylene-vinyl acetate (EVA) plastics in different concentration of silver nanoparticle were used as carriers for the bacteria adhesion. The Staphylococcus epidermidis BF model in vitro was built by shaking method. The specimens were cultured for 2d and examined by Scanning Electron Microscopy (SEM). At 0.5,1, 2d after cultivation, the biofilm was stained crystal violet and was examined with a digital microscope to calculate the biofilm coverage rate (BCR) by NIS-Element BR. The 0.5, 1 , 2, 3, 5d biofilm was stained with SYTO9/PI, monitored by Confocal Laser Scanning Microscope (CLSM). Quantification of the effect was calculated by Image Structure Analyzer (ISA) software.Conclusion: The growth kinetics of Staphylococcus epidermidis biofilm can be delayed by silver nanoparticle. With the development of time, the antibacterial effect increasingly decreased. High concentration has the better antibacterial effect than low concentration.