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Study of the bioeffects of CdTe quantum dots on Escherichia coli cells

Wang, Qisui, Fang, Tingting, Liu, Peng, Min, Xinmin, Li, Xi
Journal of colloid and interface science 2011 v.363 no.2 pp. 476-480
Escherichia coli, Fourier transform infrared spectroscopy, absorbance, byproducts, cadmium, cell growth, cell structures, cytotoxicity, dose response, fluorescence, models, nanomedicine, quantum dots, reactive oxygen species, scanning electron microscopy
Quantum dots (QDs) hold great potential for applications in nanomedicine, however, only a few studies investigate their toxic- and bio-effects. Using Escherichia coli (E. coli) cells as model, we found that CdTe QDs exhibited a dose-dependent inhibitory effect on cell growth by microcalorimetric technique and optical density (OD₆₀₀). The growth rate constants (k) were determined, which showed that they were related to the concentration of QDs. The mechanism of cytotoxicity of QDs was also studied through the attenuated total reflection–fourier transform infrared (ATR–FTIR) spectra, fluorescence (FL) polarization, and scanning electron microscopy (SEM). It was clear that the cell out membrane was changed or damaged by the addition of QDs. Taken together, the results indicated that CdTe QDs have cytotoxic effects on E. coli cells, and this effects might attribute to the damaged structure of the cell out membrane, thus QDs and by-products (free radicals, reactive oxygen species (ROS), and free Cd²⁺) which might enter the cells.