Figure 5.

SR9 facilitates QD uptake. (a) The relative QD fluorescence intensity in cells exposed to QD or QD/SR9. A549 cells were treated with 150 nM QDs and 150 nM QD/SR9 (1 : 20) for 5 min, 20 min, 40 min, and 60 min. Fluorescence intensity is normalized relative to QDs alone at 5 min. (b) and (c) QD fluorescence in cells with and without SR9 after a 5-minute exposure. (d) and (e) QD fluorescence in cells with and without SR9 after a 1-hour exposure. Images are from a single plane of Z series. Values are mean ± SD from three independent experiments. Significance is indicated by *P < .01 versus QDs-alone group.