中文摘要：

采用可表达绿色荧光蛋白的大肠杆菌（lac：：GFP）为模型,研究了新鲜的和经氯化钠溶液老化的纳米银（AgNPs）生物有效性。经0、0.5、1、2μg/m L新鲜的AgNPs处理大肠杆菌10 h后,利用酶标仪、荧光显微镜、流式细胞仪和质粒抽提试剂盒检测AgNPs毒性。经不同浓度氯化钠（Cl/Ag摩尔比分别为0、100、500、800）老化12 d后的AgNPs（0、0.5、1、2μg/m L）及其离心后相应上清处理大肠杆菌10 h后,利用紫外可见分光光度计检测AgNPs在Na Cl溶液中吸收光谱,并用酶标仪和流式细胞仪统计细菌GFP抑制率。结果表明：AgNPs抑制大肠杆菌GFP表达,影响重组质粒复制,即有显著的生长抑制作用;氯离子的存在可加速AgNPs溶解,且在老化过程中,随着Cl/Ag比例增大,AgNPs的抑制作用有所下降。

英文摘要：

Escherichia coli expressing recombinant green fluorescent protein（GFP）was used as a model system to evaluate the bioavailability of fresh AgNPs and AgNPs aged in sodium chloride（Na Cl）. The antibacterial activity of fresh AgNPs was measured using E.coli exposed to a concentration gradient of 0,0.5,1 and 2 μg/m L for 10 h with microplate reader,fluorescence microscope,flow cytometer and plasmid extraction kit. Aged AgNPs was obtained by exposing fresh AgNPs in a series of Na Cl solutions with molar ratio of Cl/Ag as 0,100,500,800 for 12 days characterized by UV-Vis spectrophotometer.The antimicrobial effect of aged AgNPs and supernatants was statistically analyzed through the inhibition rate of GFP which was detected by flow cytometer and microplate reader on exposed E.coli（10 h）. The results showed that AgNPs could significantly decrease the fluorescence intensity of GFP in E.coli and inhibit plasmid DNA replication. The presence of chloride ions can accelerate the dissolution of AgNPs. E.coli increased tolerance to AgNPs pretreated with high Cl/Ag ratio solution.