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Chen M.-F.,Southwest University | Huang C.-Z.,Key Laboratory on Luminescence and Real Time Analysis | Pu D.-Y.,Southwest University | Zheng C.-Y.,Southwest University | And 4 more authors.
Huanjing Kexue/Environmental Science

The toxic effects of CdSe/ZnS QDs on zebrafish (Danio rerio) embryos at different developmental stages were investigated in this study. The voluntary movement frequency, body length, hatching rate, mortality and malformation rate, SOD activities, MDA contents, mRNA expression of metallothionein (MT) and heat stress protein 70 (Hsp70) were used as indicators. The results showed that the EC50 was 316.994 nmol·L-1 for zebrafish embryos (72 hpf) when exposed to CdSe/ZnS QDs. After the CdSe/ZnS QDs exposure, the embryos showed a significant increase in mortality and malformation rate, a decrease in hatching rate and body length, an advance in hatching time, and a changing in the spontaneous movement frequency, and many other toxic effects, such as the condensation of embryonic eggs, the formation of pericardial cysts and curvature of the spine. Moreover, it was found that the MDA contents in the embryos in CdSe/ZnS QDs groups were significantly increased, and the SOD activities were changed. In addition, the mRNA expression level of MT and Hsp70 were up-regulated. All the information suggests that exposure of CdSe/ZnS QDs can cause toxic effects on zebrafish embryos, and the effects may be related to the releasing of Cd2+, particle size and oxidative stress. ©, 2015, Science Press. All right reserved. Source

Yu L.,Southwest University | Yu L.,Key Laboratory on Luminescence and Real Time Analysis | Yu L.,Guiyang Environmental Monitoring Center | Liu Z.,Southwest University | And 7 more authors.
Microchimica Acta

The intensities of resonance Rayleigh scattering (RRS) of poly (vinyl pyrrolidone) (PVP) and of eosin Y (EY) are weak in solutions of pH 2.9 to 3.4. If reacted with each other, the intensities of RRS are largely enhanced and new RRS bands appear at 276 nm and 320 nm. The intensity at 276 nm is linearly related to the concentration of PVP in the range from 0.10 to 1.6 μg mL-1. The correlation coefficient is 0.9987, and the detection limit is 28.7 ng mL-1. The binding mode between PVP and EY was studied by RRS, and by absorption and fluorescence spectroscopy. The optimum reaction conditions and some potential interferences were investigated. The method displays good selectivity and was applied to the determination of PVP in beer. © Springer-Verlag 2010. Source

Peng J.,Key Laboratory on Luminescence and Real Time Analysis | Liu S.,Key Laboratory on Luminescence and Real Time Analysis | Yan S.,Key Laboratory on Luminescence and Real Time Analysis | Fan X.,Key Laboratory on Luminescence and Real Time Analysis | He Y.,Key Laboratory on Luminescence and Real Time Analysis
Colloids and Surfaces A: Physicochemical and Engineering Aspects

Thioglycolic acid (TGA) capped CdTe quantum dots (QDs) with the diameter of 2-3 nm were synthesized. The interaction between CdTe QDs and chymotrypsin (chy) was investigated by ultraviolet-visible (UV-vis) absorption, fluorescence and resonance Rayleigh scattering (RRS) spectroscopy. Under pH 7.2, CdTe QDs effectively quenched the intrinsic fluorescence of chy via static quenching. The binding constants for the formation of a complex between CdTe QDs and chy were 2.85, 2.58, 2.48 × 103 M-1 at 293, 298 and 303 K, respectively. ΔS° (49.72 kJ mol-1) and ΔH° (-4.61 kJ mol-1) indicated that electrostatic attraction was the dominant intermolecular forces in stabilizing the complex. The interaction between CdTe QDs and chy lead to the remarkable enhancement of RRS and the enchantments were in proportional to the concentration of chy in a certain range. The reasons for the enhancement of RRS were discussed. The experimental results showed that chy molecules have a relatively high affinity with CdTe QDs. © 2010 Elsevier B.V. All rights reserved. Source

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