Patent ID: 7527940

Claim:
A method of measuring a change in cellular morphology comprising: a) exposing a region containing a sub-population of cells in a cell population to an activation light of a first wavelength, wherein said cell population is labelled with a non-fluorescent caged fluorescent molecule, to irreversibly activate said caged fluorescent molecule in the sub-population of cells to an active fluorescent form; b) at a first subsequent time exposing at least a portion of said cell population to a fluorescent excitation light of a second and different wavelength and detecting a first pattern of distribution of said fluorescent molecule; and c) at a second time exposing said portion of said cell population of step (b) to light of the second wavelength and detecting a second pattern of distribution of said fluorescent molecule; wherein a difference between said first and second patterns of distribution of said fluorescent molecule is indicative of a change in said cellular morphology and further wherein said method does not include tracking of individual cells.