Evaluation of biological activity of quantum dots in a microsystem.

The presented work aimed at systematic investigation of biological activity of CdSex S1- x /ZnS and CdSe/ZnS quantum dots (QDs), whose surface was modified with different ligands. For these studies, we used a microfluidic system combined with fluorescence microscopy techniques, which enabled analysis of cells' morphology, viability, and QDs uptake. PDMS and glass-based microfluidic system enabled the precise control of the cell environment, allowed to examine five replications of each tested QDs concentrations (statistically significant number), monitor multiple cellular events, and avoid manual preparation of QDs dilutions. We investigated the influence of the core composition and the type of surface modifiers on QDs toxicity. We also determined whether the examined nanoparticles penetrate into the cells. For all tested nanoparticles, the decrease of cells' viability was observed when increasing nanoparticles concentration. The decrease of live cells' number in microchambers and the accumulation of the nanoparticles around cultured cells were observed. The effect of hydrocarbon chain length of surface modifiers and QDs core composition on the cell viability was confirmed in our tests.