A microfluidic device was developed for flow cytometry and single cell fluorescence detection. TO-PRO-3 as a vital DNA dye was used to label dead cells and some of apoptosis cells which could be penetrated from their broken membranes and intercalated into DNA chains. Cells were driven by combined effect of hydrodynamic and electric power and passed through the detection point one by one in micro channels. A laser induced fluorescence detection system which employed a 635 nm semiconductor laser was the only measurement of the whole system. This micro flow cytometor system was applied to estimate the damage degree of those HeLa cells having been exposed to ultraviolet radiation for 10, 20 and 40 min, respectively by the number of cells determined and their fluorescence intensity.
