Studies on influence of polymer modifiers for fluorescent nanocrystals’ cytotoxicity

• Low weight HBPGs are effective CdSeS/ZnS QDs stabilizers.
• Cytotoxicity of CdSeS/ZnS QDs on A549 tumor cells was assessed.
• QDs stabilized with various derivatives of HBPG exhibit different cytotoxicity.
• HBPG-modified CdSeS/ZnS QDs do not enter a549 cells via endocytosis.

The presented studies aimed at investigation of the effect of CdSeS/ZnS quantum dots (QDs) stabilized with hyperbranched polyglycidol and its carboxylated derivative on adenocarcinomic human alveolar basal epithelial cells (A549). The first stage of studies concerned the modification of quantum dots with both types of the tested polymers with the use of pyridine as an intermediate agent. Subsequently, cytotoxic effect of the prepared nanoparticles was examined after various incubation time using MTT test (cell metabolic activity assay). Our studies revealed that CdSeS/ZnS with a diameter of 6 nm, which were stabilized with hyperbranched polymers do not penetrate into cells, even after prolonged incubation time. Moreover, the cytotoxic effect of the tested QDs was observed over a range of tested concentrations (5–90 μM of Cd2+). It was confirmed that tested nanoparticles had significant influence on cell culture viability. The examined cytotoxic effect of the tested quantum dots was dependent on the type of polymer applied and the experiments indicated, that the one bearing carboxylic moieties is more toxic to A549 cells.