Comparative study of cytotoxicity by platinum nanoparticles and ions in vitro systems based on fish cell lines.

Emission of platinum nanoparticles (Pt NPs) especially from vehicle exhaust catalysts and pharmaceutics cause an increase in concentrations of this metal in aquatic environments. In this study, small (4-9 nm) uncoated and polyvinylpyrrolidone (PVP) coated Pt NPs were synthetized and their dispersion in different exposure media were evaluated. Pt NP uptake in two established fish cell lines were investigated and comparative in vitro cytotoxicity of Pt NPs and ions were assessed. The coated and uncoated Pt NPs dispersions in minimum essential medium (MEM) with fetal bovine serum (FBS) displayed high colloidal stability. Transmission electron microscopy (TEM) and high-resolution scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (STEM/EDX) indicated no detectable cellular uptake of Pt NPs in both cell line monolayers. But with ICP-MS analysis, trace amount of Pt content was determined in all digested monolayer cell samples. The cytotoxicity of both Pt NPs and Pt ions on both fish cell lines after 48 h exposure was investigated through three assays to monitor different endpoints of cytotoxicity. In all studied concentrations (0.325-200 mg/L) no significant cytotoxicity (p > .5) compared to controls were observed in the cells exposed to coated Pt NPs. Uncoated Pt NP and ion exposed cells indicated similar concentration dependent cytotoxicity on both cell lines.