Integrated microfluidic system with chemiluminescence detection for single cell analysis after intracellular labeling.

This work describes the first application of microchip electrophoresis with chemiluminescence detection (MCE-CL) in single cell analysis. Human red blood cells were assayed to determine intracellular content of glutathione (GSH). Intracellular GSH was first labeled by incubating cells with diazo-luminol, and then individual cells were injected, in-line lysed, and MCE separated. CL detection was based on the oxidation reaction of luminol-labeled GSH with NaBrO. The MCE-CL assay had a linear calibration curve over a range from 0.2-90 amol GSH injected with a correlation coefficient of 0.9991 and a detection limit of 50 zmol or 3.6 x 10(-9) M (S/N = 3). The average content of GSH in individual human red blood cells was found 64.9 amol (n = 17). Compared with the MCE methods with laser induced fluorescence detection (LIF) reported so far for single cell analysis, the present MCE-CL assay of GSH is simple and about 100 times more sensitive.