Cytotoxicity of aged cadmium-telluride quantum dots to rainbow trout hepatocytes

The purpose of this study was to examine the lethal and sublethal toxicity of cadmium telluride (CdTe) quantum dots (Q-dots) in primary cultures of rainbow trout hepatocytes. Hepatocytes were exposed to concentrations of positively coated and aged (2 months and 2 years) Q-dots for 48 h at 15°C. Post treatment, cellular analysis was done of cell viability, lipid peroxidation (LPO), DNA damage, metallothioneins (MT), labile zinc/cadmium and heat shock proteins (chaperones). Q-dots were found to be toxic to fish hepatocytes at a threshold concentration of 0.1 mg/l. These nanoparticles increased the levels of MT, labile zinc, DNA strand breaks and heat shock proteins of the 70 kDa family. The strongest response was observed with the molecular chaperone of the 70 kDa family, reaching a 7-fold induction in exposed cells. Overall, the assessment of multiple biomarkers in trout hepatocytes exposed to differently ‘aged’ Q-dots suggests that the cytotoxic responses to two-year-old positively coated CdTe Q-dots were largely due to the liberation of Cd2+.