Quantifying the Influence of Surface Coatings on Quantum Dot Uptake in Cells

In this study, we use photoluminescence to quantify quantum dot uptake by SK-BR-3 human breast carcinoma cells as a function of quantum dot surface coating (bare, 750 MW PEG, 6000 MW PEG), concentration, and incubation time. Results demonstrated significant differences in nanoparticle uptake based on surface coatings, concentration, and incubation time. Non-PEGylated QDs exhibited a five-fold increase in endocytic uptake compared to PEGylated QDs. Transfection-assisted delivery with Lipofectamine 2000 yielded a 53% increase in QDs per cell over controls. Although previous work has qualitatively examined QD uptake, to the best of our knowledge, this is the first report to quantify intracellular uptake of quantum dots as a function of these parameters.