Effects of Surface Charges on the Bactericide Activity of CdTe/ZnS Quantum Dots: A Cell Membrane Disruption Perspective.
The inhibitory effects of CdTe/ZnS quantum dots (QDs) modified with 3-mercaptopropionic acid (negatively charged) or cysteamine (positively charged) on the metabolic activity of Escherichia coli were investigated using biological microcalorimetry. Results show that the inhibitory ratio of positive QDs is higher than that of negative QDs. Transmission electron microscopy images indicate that QDs are prone to be adsorbed on the surface of E. coli. This condition disturbs the membrane structure and function of E. coli. Fluorescence anisotropy results demonstrate that positive QDs show a significant increase in the membrane fluidity of E. coli and dipalmitoylphosphatidylcholine (DPPC) model membrane. Furthermore, fluorescence anisotropy values of DPPC membrane in the gel phase decreased upon the addition of positive QDs. By contrast, anisotropy values in the liquid-crystalline phase are almost constant. The change in membrane fluidity is associated with the increased permeability of the membrane. Finally, the kinetics of dye leakage from liposomes demonstrate that the surface charge of QDs is crucial to the interaction between QDs and membrane.
College of Chemistry and Environmental Engineering, Yangtze University , Jingzhou, Hubei 434023, P. R. China.
Lu
0000-0002-1254-7711
L
Lai
College of Chemistry and Environmental Engineering, Yangtze University , Jingzhou, Hubei 434023, P. R. China.
Sheng-Jin
SJ
Li
College of Chemistry and Environmental Engineering, Yangtze University , Jingzhou, Hubei 434023, P. R. China.
Jing
J
Feng
College of Chemistry and Environmental Engineering, Yangtze University , Jingzhou, Hubei 434023, P. R. China.
Ping
P
Mei
College of Chemistry and Environmental Engineering, Yangtze University , Jingzhou, Hubei 434023, P. R. China.
Zhao-Hua
ZH
Ren
College of Chemistry and Environmental Engineering, Yangtze University , Jingzhou, Hubei 434023, P. R. China.
Yan-Ling
YL
Chang
State Key Laboratory of Virology & Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecule Sciences, Wuhan University , Wuhan 430072, P. R. China.
Yi
0000-0001-7626-0026
Y
Liu
D019187:Cadmium Compounds / Q000737:chemistry / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects*; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D045663:Quantum Dots / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry / Q000494:pharmacology*; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry / Q000494:pharmacology*; D017967:Zinc Compounds / Q000737:chemistry / Q000494:pharmacology*
D019187:Cadmium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C031238:zinc sulfide; D013691:Tellurium; C028337:cadmium telluride