Fig. 4

Confocal images of THP-1 cells exposed to 50 µg/ml of PS NPs. a Demonstrates THP-1 cells exposed to PS NPs of 40 nm, 100 nm and 200 nm for 4 h. b, c Display THP-1 cells exposed to 50 µg/ml of 40 nm PS NPs for 1 h and 4 h, respectively, and whether or not (‘Control’) treated with 0.83 U/ml neuraminidase for 30 min prior to PS NP exposure. PS NPs are yellow-green fluorescently labelled (green) (a–c), cell membrane associated proteoglycans were stained by Alexa Fluor^® 555 conjugated wheat germ agglutinin (red) (a–c), nuclei were stained using Hoechst 33342 (blue) (a) and the lipid bilayer was stained using DiD (violet) (b, c). Images were collected between 30 min and 1 h after loading and subsequent staining. Scale bar: 5 µm