Fig. 3

Cellular association of PSNPs with a different surface chemistry by Caco-2 cells. Adhesion and uptake was determined by single-cell HC image analysis of PSNP fluorescence. a Time dependent adhesion and uptake of four types of PSNPs in Caco-2 cells exposed to a nominal concentration of 50 µg PSNPs/ml for 10 up to 120 min. b Cellular association distribution profiles of 50 nm (-SM) PSNPs in the entire cell population at exposure to nominal concentration ranging from 15 to 250 µg/ml for 30 min. Note that the readings at the highest concentrations are hampered by saturation of the HC signal. c Concentration dependent cellular association of four types of PSNPs after 30 min of exposure (//; the fluorescence intensities of 50 nm (-SM) is plotted on the left y-axis while the rest of the PSNPs fluorescence intensities are plotted on the right y-axis). ^#Significant difference versus all lower concentrations (P < 0.05). *Significant difference between indicated concentrations (P < 0.05)