Fluorescein dye is the most commonly used fluorescent probe. It is used to stain epithelial defects and analyse the integrity of corneal epithelium.

Store at -20°C in dark.

Transepithelial transport experiments 1. Monolayer cells are cultured in a Transwell insert set in a 12-well plate. After appropriate culture time (e.g., Caco-2 cell for 21 days), culture medium is removed, wash the apical side and basolateral side with preheated HBSS for two times. 2. For measurement of apical-to-basolateral permeability, 1.5 ml of HBSS (pH 7.4, 37°C) is added to the basolateral side, and 0.5 ml of the test solution (pH 6.0, 37°C) containing 0.04% fluorescein is added on the apical side of the inserts. 3. After the well is incubated for an appropriate time at 37°C, samples are collected from the basolateral solution. 4. The fluorescent compounds transported by the cells are estimated with a fluorescence spectrophotometer at the excitation wavelength of 490nm and emission wavelength of 514nm. The results are expressed as the proportion of the original amount that permeated through the monolayer, which was calculated as the amount transported divided by the initial amou

Fluorescein dye is the most commonly used fluorescent probe. It is used to stain epithelial defects and analyse the integrity of corneal epithelium. Fluorescein is used in the diagnosis of corneal perforation. Oral or intravenous fluorescein is used in fluorescein angiography to detect diabetic retinopathy and choroidal neovascular membrane. λex 490 nm; λem 514 nm in 0.1 M Tris pH 8.0.