CYTOTOXICITY EVALUATION OF TITANIUM AND ZINC OXIDE NANOPARTICLES ON HUMAN CELL LINES

Abstract

Objective: In vitro cytotoxicity evaluation of titanium dioxide, 20 nm (TNP 20) and zinc oxide, 20 nm (ZNP 20) nanoparticles (NP) were tested on different types of human skin (HaCat), lung (A549), liver (Hep G2) and colon (Caco-2) cell cultures in relevance to human risk assessmentMethods: The different concentrations of test TNP 20 and ZNP 20 1-300 µg/ml were exposed to determine the cell viability reduction on four human cell lines after 48 h post exposure using 3-(4, 5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). The mitochondrial membrane activities of the viable cells were determined with intensity of formazon formation by interpreting ELISA absorbance values at 470 nm.Results: The percent of cytotoxicity was determined by comparing percentage of cell viability reduction of test with that of control. The ZNP 20 produced higher cytotoxicity at the doses 100 (p<0.05) and 300 (p<0.001) µg/ml significantly on tested four human skin (HaCaT), lung (A549), liver (Hep G2) and colon (Caco-2) cells compared to TNP 20. The tested NP induced lesser cytotoxicity at lower concentrations with 1 and 3µg/ml in all the tested four cell lines. The induced cytotoxicity was an indicator for increased intracellular reactive oxygen species which further cause’s major cell damage and cell death.Conclusion: The tested NP were induced greater cytotoxicity in the colon, Liver, lung and skin cells at higher concentrations 100 and 300 µg/ml significantly. The cytotoxicity order of TNP 20 and ZNP 20 at the highest dose (300µg/ml) were concluded as Caco-2>Hep G2>A549>HaCaT for 48 h post exposed cells.