Laurdan (6-Dodecanoyl-2-dimethylaminonaphthalene) is a fluorescent membrane probe that is spectrally sensitive to the phospholipid phase of the cell membrane to which it binds.

Laurdan as a biosensor to monitor changes in membrane water content during NIH3T3 cell migration
I. Solution preparation
1. Preparation of storage solution: Dissolve Laurdan in dimethyl sulfoxide (DMSO) to prepare a 1.8 mM stock solution.
2. Preparation of working solution: Dilute the Laurdan stock solution at a dilution of 1:1000.
II. Operation steps
1. Culture NIH3T3 cells in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum, 5 mL Pen-Strep, and 2.5 mL 1 M HEPES.
2. Seed freshly isolated NIH3T3 cells into 35 mm Mattek glass-bottom culture dishes coated with fibronectin.
3. Incubate the cells with Laurdan at 37°C for 40 min.
4. Observe using an LSM710 META laser scanning microscope.
5. Calibration of the system and phasor plot of FLIM data by measuring fluorescein (pH 11).