Figure 4.
In vitro fluorescein isothiocyanate (FITC)-labeled folate-receptor targeted nanoparticles (FRNPs) and blank NPs (green dots) binding with 3 types of cancer cells (red area) were observed under a fluorescence microscope. FRNPs were visibly uptaken into the cytoplasm of both Bel7402 cells and SW620 cells, whereas A549 cells just bound with few FRNPs. None of the 3 types of cells displayed prominent binding to blank NPs.