【摘要】 以大肠杆菌为研究对象,对纳米银的抗菌效果进行了研究,并对其抗菌机制做了初步探讨。纳米银对大肠杆菌的抑制生长曲线的结果表明,20μg/mL的纳米银能够完全抑制106cfu/mL的大肠杆菌细胞生长,纳米银使大肠杆菌的延滞期加长,并且纳米银浓度越高,延滞期越长。采用透射电镜观察了经纳米银粒子处理过的大肠杆菌细胞形态变化过程,结果显示纳米银粒子先在细胞壁上产生小的孔洞,通过这些孔洞进入周质空间,导致细胞膜成分渗漏和破坏细胞膜,进而进入细胞内部。进入细胞内部的纳米银粒子使DNA浓缩呈紧张态,并与破损细菌的细胞质结合积聚,最后引起胞内物质流失。另外,纳米银对大肠杆菌总DNA影响的分析表明,随着纳米银浓度的增高,大肠杆菌总DNA样品降解的程度增大。更多还原

【Abstract】 The antimicrobial effect of the nanosilver on Escherichia coli and the antimicrobial mechanism was studied elementarily.Experimental results indicated that the silver nanoparticles of 20 μg/mL could inhibit completely the growth of 106 cfu/mL cells in liquid LB medium.The growth curves showed that silver nanoparticles prolonged the lag phase of E.coli,and the higher of the concentration of silver nanoparticles,the longer of the lag phase of E.coli.Transmission electron microscopy(TEM) was used to evaluate the cell morphology of both the normal and the treated E.coli.The observation with TEM suggested that silver nanoparticles lead to the formation of "pits" in cell wall of the bacteria,and silver nanoparticles could enter into periplasm through the pits and destroyed the cell membrane.Then the silver nanoparticles could enter into the bacterial cell,which not only condensed DNA,but also combined and coagulated with the cytoplasm of damaged bacteria.Finally,silver nanoparticles resulted in the leakage of cytoplasmic component.Moreover,the analysis of agar gel electrophoresis demonstrated that silver nanoparticles could increase the decomposability of genome DNA.更多还原