FITC-PEG1000-NH2

As a membrane-impermeable fluorescent dye, FITC-NH₂ shows no intracellular fluorescence in PC-3 cell uptake assays; FITC-NH₂-labeled polymers (10 μM; 24 h) exhibit a punctate vesicle staining pattern in PC-3 cells, suggesting that the polymers enter cells via the endocytic pathway and localize to lysosomes^[2].
Procedure^[2]:
(1) Seed PC-3 cells into 8-well Lab-Tek^TM chamber slides, and culture the cells in a 37 °C, 5% CO₂ incubator for 24 h.
(2) Discard the culture medium, and wash the cell monolayer once with RPMI-1640 medium.
(3) Dilute FITC-labeled polymers to 10 μM with serum-free RPMI-1640 medium, and add the solution into the chambers; set up a free FITC-NH₂ control group at the same time.
(4) Incubate the cells at 37 °C for 24 h.
(5) Discard the drug-containing medium, and wash the cells six times with DPBS.
(6) Add 4% buffered formalin, and fix the cells at room temperature for 10 min.
(7) Wash the cells three times to remove residual formalin.
(8) Stain cell nuclei with TO-PRO-3 according to the manufacturer’s protocol.
(9) After washing, mount the cell monolayer onto the slide with fluorescent mounting medium.
(10) Observe the cellular uptake and distribution using a Nikon C1 laser scanning confocal microscope.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.