FITC Dextran Permeability Assay

1 mg FITC Dextran (Cat#T18988, Targetmol, USA) was dissolved in 1 ml double-distilled water to obtain a stock solution with a concentration of 1 mg/ml. The stock solution was diluted with serum-free medium to a working concentration of 500 μg/ml. After this intervention, PBS was added for washing twice. 100 μl FITC Dextran (500 μg/ml) was added to the upper compartment, and 600 μl serum-free basal medium was added to the lower compartment. After 1 h incubation in the dark, 100 μl medium was aspirated from each compartment and loaded onto a black 96-well plate. The OD value was measured at 495nm/520nm using a multi-functional enzyme reader (MD, USA). The permeability was calculated [25 (link)].