Fig. 3.

The effect of particle size on kinetics of phagosomal pH and intracellular localization. (a) Phagosomal pH calibration curves determined by the ratio of OVA–FITC to OVA– AlexaFluor647 (FL1/FL3) conjugated to 50 nm, 500 nm, and 3 μm polystyrene beads. (b) Beads were delivered to cells at a concentration of 100 μg/ml OVA–FITC. The phagosomal pH profiles of 50 nm, 500 nm, and 3 μm polystyrene beads were determined at varying time points. (c) 3 μm and 50 nm fluorescent polystyrene beads (green) were incubated with DCs for 30 min, washed, further incubated for either 30 or 120 min and examined by confocal microscopy to determine the intracellular localization of beads. DCs were labeled with LysoTracker Red (red) to label lysosomes and DAPI (blue) to label nuclei.