A method for characterizing cell membrane order in a cell. The method includes: staining the cell with di-4-ANEPPDHQ to produce a stained cell; irradiating the stained cell with an excitation light, the excitation light being capable of inducing fluorescence in the di-4-ANEPPDHQ; measuring a fluorescence spectrum of the stained cell; and characterizing the cell membrane order by computing a spectral signature of the stained cell from the fluorescence spectrum, the spectral signature providing a character of the cell membrane order.
QUANTIFICATION OF CHANGES IN THE DEGREES OF ORDER OF CELLULAR AND VIRAL MEMBRANES AND APPLICATIONS TO DIAGNOSIS, TREATMENT AND DRUG SCREENING