Hi Xiangju,

You may check the link below regarding Lucifer Yellow Permeability Assay.

In our vascular permeability experiments, we check monolayer integrity using 70kDa FITC-Dextran: size of dextran determines whether it will permeate through the monolayer, so the size can be adjusted accordingly; the FITC gives the fluorescence signal.

Although I have not used Lucifer Yellow before, I think it works with the same principle as that of the FITC-dextran but requires a different fluorescence excitation/emission to measure the fluorescence signal. I guess in this case, there's no right or wrong assay for your peameability assay, whatever suits for your application that works is okay.

Sincerely,

John

http://csmedia2.corning.com/LifeSciences/media/pdf/protocol_DL_GT_035_Lucifer_Yellow_Permeability_Assay_using_Falcon_HTS_96_Multiwell_Insert_Systems.pdf

I agree with John, alternatively you can just measure the resistance of the cell monolayer.

Consider crystal violet.

Many thanks everyone.