纳米银对荧光假单胞菌生物膜形成的影响

Effect of silver nanoparticles on biofilm formation of Pseudomonas fluourcens

分别以空白和0.4%纳米银乙烯醋酸乙烯酯(EVA)塑料片作为载体培养荧光假单胞菌生物膜,通过菌落计数法测定生物膜的变化曲线,分别采用普通显微镜观察生物膜形成并计算覆盖率(BCR),扫描电镜观察生物膜的微观结构,激光共聚焦显微镜观察生物膜中的细菌状态并计算死亡率.结果表明,空白、纳米银EVA表面生物膜分别在12和24h达到稳定状态,各时间点的纳米银EVA表面菌数及BCR均显著低于空白EVA(p<0.05);在10000倍的视野下,空白EVA表面的荧光假单胞菌通过胞外产物和菌体形成致密生物膜,纳米银EVA表面多为分散菌体;在24,48h时,纳米银EVA表面的死亡菌体数显著高于空白EVA(p<0.05);纳米银通过抑制荧光假单胞菌生长和减少胞外产物的分泌而影响生物膜的形成.

To explore the effect of silver nanoparticles on the formation of Pseudomonas fluourcens biofilms on ethylene-vinyl acetate（EVA）pieces,the curve of bacterial biofilm is determined by colony counts,and the morphology,microstructure and bacterial status of the biofilm are respectively observed through crystal voilet staining,scanning electron microscopy（SEM）and confocal laser scanning microscope（CLSM）.The biofilm stained by crystal violet is examined with a digital microscope to calculate the biofilm coverage rate（BCR）by NIS-Element BR soft ware.Then the mortality of bacterial is calculated by image structure analyzer（ISA）software.Results show that the bacteria can aggregate on the control EVA and EVA contained 0.4% silver nanoparticles,and forms the grown biofilm after 12 and 48hculture,respectively.But the biofilm on the control EVA has more bacterial count and BCR than that of silver nanoparticles（p〈0.05）.At 24 h,the bacteria interacting with its extracellular products can form the dense film in the microscope vision of 10 000 times on the control EVA,while there are only dispersive bacteria on silver nanoparticle EVA.The bacterial mortality in the film on silver nanoparticle EVA is significantly higher than that of control group at 24,48h（p〈0.05）.Silver nanoparticles have great inhibiting effect on biofilm formation of Pseudomonas fluourcens through inhibiting the growth of the bacterial and its extracellucar products.