Determination, characterization and cytotoxicity on HELF cells of ZnO nanoparticles

Three kinds of ZnO nanoparticles (NPs) with different size were characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD). The potential cytotoxicity of ZnO NPs with various concentrations has been investigated using human embryonic lung fibroblasts (HELF) cells. The cytotoxicity of ZnO NPs on the normal HELF cell was evaluated by 3-(4,5-dimethylthiazol)-2,5-diphenltetrazoliumhromide (MTT) assay and characterized with photo microscopy and scanning electron microscopy (SEM). The results indicated that ZnO NPs aqueous suspensions with concentrations varying from 2.5 to 150 mg L−1 were harmful to the HELF cells and the cytotoxicity to HELF showed obviously concentration dependence. With concentrations higher than 20 mg L−1, ZnO NPs led to the livability of the tested cells lower than 10%. These results highlighted the need for caution during the use of ZnO NPs above 1.2–1.6 mg L−1 for safety. Finally, an UV–vis spectroscopic approach was developed for the determination of ZnO NPs concentration in the linear range 2–50 mg L−1 (correlation coefficients more than 0.9990), and the detection limit was 1.0 mg L−1.