Mechanism of antimicrobial activity of CdTe quantum dots.
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.
Lu
Zhisong
Z
School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore.
Li
Chang Ming
CM
Bao
Haifeng
H
Qiao
Yan
Y
Toh
Yinghui
Y
Yang
Xu
X
D000890:Anti-Infective Agents; D000975:Antioxidants / Q000737:chemistry; D001419:Bacteria / Q000378:metabolism; D001422:Bacterial Adhesion; D015374:Biosensing Techniques; D019187:Cadmium Compounds / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D015536:Down-Regulation; D004926:Escherichia coli / Q000378:metabolism; D018625:Microscopy, Atomic Force / Q000379:methods; D018613:Microscopy, Confocal; D008954:Models, Biological; D045663:Quantum Dots; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry*
D000890:Anti-Infective Agents; D000975:Antioxidants; D019187:Cadmium Compounds; D002244:Carbon; D013691:Tellurium; C028337:cadmium telluride