In vitro cytotoxicity of zinc oxide, iron oxide and copper nanopowders prepared by green synthesis

In vitro cytotoxic effects of ZnO, FeO and Cu metallic nanopowders (NPs) on Vero (African green monkey kidney cell line), PK 15 (Pig kidney cell line) and Madin Darby Bovine Kidney (MDBK) cell lines were investigated at different time intervals (24 and 48 h). MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to determine the cytotoxic effects of green synthesized (plant based) nanopowders. The comparative effects of exposure period and concentration of nanopowders on cell viability were studied. Green synthesized nanopowders showed varying activity on different type of cells and the effect was generally based on the concentration and exposure time. In MDBK cells, only ZnO nanopowder (NP) showed significant effect on cell viability. The ZnO NP showed improved cell viability at lower concentration (10 mu g/100 mu l) in all type of cells (Vero, PK 15 and MDBK cells). In contrast, FeO NP showed better activity at the concentration of 10 mu g/100 l, 50 mu g/100 mu l and 40 mu g/100 mu l after 24 h exposure time in Vero, PK 15 and MDBK cells respectively. However better cell viability was observed in Cu NP treated Vero, PK 15 and MDBK cells at 40 mu g/100 mu l, 20 mu g/100 mu l and 10 mu g/100 mu l correspondingly. These studies suggested that the activity of green synthesized NPs were highly dependent on concentration, exposure time and type of cells.