Lu Zhisong, Li Chang Ming, Bao Haifeng, Qiao Yan, Toh Yinghui, Yang Xu
School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore.
Langmuir. 2008 May 20;24(10):5445-52. doi: 10.1021/la704075r. Epub 2008 Apr 18.
The antimicrobial activity and mechanism of CdTe quantum dots (QDs) against Escherichia coli were investigated in this report. Colony-forming capability assay and atomic force microscopy (AFM) images show that the QDs can effectively kill the bacteria in a concentration-dependent manner. Results of photoluminescence spectrophotometry, confocal microscopy, and antioxidative response tests indicate that the QDs bind with bacteria and impair the functions of a cell's antioxidative system, including down-regulations of antioxidative genes and decreases of antioxidative enzymes activities. The oxidative damage of protein and lipid is also observed with thiobarbituric reacting substances and protein carbonyl assays, respectively. On the basis of these results, it is proposed that the mechanism of the antimicrobial activity of CdTe QDs involves QDs-bacteria association and a reactive oxygen species-mediated pathway. Thus, CdTe QDs could have the potential to be formulated as a novel antimicrobial material with excellent optical properties.
本报告研究了碲化镉量子点（QDs）对大肠杆菌的抗菌活性及作用机制。菌落形成能力测定和原子力显微镜（AFM）图像表明，量子点能以浓度依赖的方式有效杀灭细菌。光致发光分光光度法、共聚焦显微镜和抗氧化反应测试结果表明，量子点与细菌结合并损害细胞抗氧化系统的功能，包括抗氧化基因的下调和抗氧化酶活性的降低。分别通过硫代巴比妥酸反应物和蛋白质羰基测定法也观察到了蛋白质和脂质的氧化损伤。基于这些结果，提出碲化镉量子点的抗菌活性机制涉及量子点与细菌的结合以及活性氧介导的途径。因此，碲化镉量子点有可能被制成具有优异光学性能的新型抗菌材料。
