2.7. Cellular Uptake of Nanoparticles Observed by Fluorescence Microscope

To determine the cellular uptake of nanoparticles, DPCs were cocultured with cy3-labeled miRNA/PEG-PEI nanoparticles, and the absorption ratio was observed under fluorescence microscope. DPCs were seeded in 6-well plates at a density of 2 × 10⁵/well. The nucleuses of cells were stained with Hoechst 33342 for 10 m and washed in PBS for 3 times. cy3-miRNA/PEG-PEI was prepared at designated N/P ratio of 2. DPCs were incubated with the solution for 0, 1, 2, and 4 h. The images were captured under microscope (Axiovert, Zeiss, Germany) to observe the cellular uptake of nanoparticles.