Abstract:

Objective
To investigate the hepatotoxicity and DNA damage induced by thioglycolic acid (TGA)-capped cadmium telluride (CdTe) quantum dots(QDs) in human hepatic cells HL-7702,and to provide experimental evidence for the toxicological research and safety evaluation.Methods The HL-7702 cells were divided into control group and CdTe QDs-treated groups with different concentrations of CdTe QDs(0,6.25,12.50,25.00 and 50.00 mg/L, respectively).After  treated with CdTe QDs,the cell proliferation was measured by MTT assay,the DNA damage by single cell gel electrophoresis (SCGE),the cell cycle process by propidium iodide (PI)-flow cytometry (FCM) and the  apoptosis by acridine orange/ethidium bromide (AO/EB) assay and Annexin Ⅴ- fluorescein isothiocyanate (FITC)/PI-FCM.Results The MTT results showed that CdTe QDs inhibited the proliferation of HL-7702 cells in a dose-dependent and time-dependent manner.The results acquired by SCGE and FCM with PI staining showed that after CdTe QDs exposure for 24 h,as exposure dose increased,the degree of DNA damage raised, and the percentage of HL-7702 cells in G0/G1 phase was decreased while they were significantly increased in S and G2/M phases (P<0.05).In AO/EB assay,the apoptotic cells were observed under fluorescence microscope;In Annexin Ⅴ-FITC/PI-FCM,the apoptotic rates in CdTe QDs groups were significantly increased compared with  control group (P<0.05). Conclusion CdTe QDs could influence the cell viability,and induce DNA damage,S and G2/M phases arrest and apoptosis in HL-7702 cells.

Key words: cadmium telluride;quantum dots;cell viability;DNA damage;cell cycle;apoptosis