A fixed cytometer chip for identification of cell populations and real-time monitoring of single-cell apoptosis under gradient UV radiation

Cytometry is a basic method to determine cell populations and morphology. Flow cytometry and hemocytometry are the two most common methods among cytometric technologies. However, flow cytometry needs bulky and expensive equipment as well as professional operations, while hemocytometry is limited by its simple function. Both of them are not suitable for real-time monitoring of the morphological changes of single cells. Here, we developed a fixed cytometer chip with two functional modes for both identification of cell populations (I-mode) and real-time monitoring of single-cell morphological changes (M-mode). In I-mode, the fixed cytometer chip was employed to evaluate the cell populations, the results were in accordance with those from the hemocytometer counting and flow cytometry. Besides that, the cell populations were further precisely identified by measuring two-color fluorescence intensities of single cells, which were consistent with the dual parameter analysis in flow cytometry. In M-mode, the chip was applied to real-time monitoring of the single-cell apoptosis under gradient UV radiation, generated by a novel stair-like UV shield. The dynamic apoptotic morphologies of a large number of single cells were monitored in real-time by time-lapse imaging. In addition, we integrated eight parallel channels on a 60 mm × 30 mm chip, and the chip could achieve scalable single-cell capture and analysis capability. This fixed cytometer chip is bifunctional, easy-to-handle, universal, and scalable.