The cytotoxicity of CdTe quantum dots and the relative contributions from released cadmium ions and nanoparticle properties

A systematic study was carried out on the relationship between the cytotoxicity of quantum dots (QDs) and free cadmium ions using CdCl2 solution with known amounts of Cd2+ as the control. We found that the CdTe QDs were more cytotoxic than CdCl2 solutions even when the intracellular Cd2+ concentrations were identical in HEK293 cells treated with them, implying the cytotoxicity of CdTe QDs cannot attributed solely to the toxic effect of free Cd2+. Moreover, we discovered that the cytotoxicity of QDs was based on the concentration of total QDs ingested by cells. Our data clearly showed that specific properties of nanopartices have an obvious influence on their cytotoxicity.