Cellular Uptake Assay

Cellular uptake and intracellular distribution of NPs were studied by confocal laser scanning microscopy and fluorescence microplate reader. Briefly, PANC-1 and Patu8988T were seeded in 6-well plates overnight. Then, coumarin-6 (C6) solution and C6-labelled nanoparticles (C6@NPs or C6A@NPs) were added into the cultured cells and incubated for pre-determined time at 37°C. Following that, the cells were washed twice with PBS and immobilized by 4% paraformaldehyde for 15 min at room temperature. The fluorescence images were recorded by a confocal laser scanning microscope (Nikon Corporation, Tokyo, Japan), and the fluorescence intensity was measured by a fluorescent microplate reader (Infinite 200Pro, Tecan i-control) by setting the excitation/emission wavelengths at 466 nm/504 nm.