Cellometer Image Cytometry as a Complementary Analysis Tool to Flow Cytometry for Visual Verification of Gated Cell Populations

Dmitry Kuksin, Christina Arieta Kuksin, Leo L. Chan, Bo Lin, Jean Qiu, and Peter Y. Li

Traditionally, many cell-based assays that analyze cell populations and functionalities have been performed using flow cytometry. However, flow cytometers remain relatively expensive, and require highly trained operators for routine maintenance and data analysis. Flow cytometer can process and generate a large number of events, but the data gating strategies are often complex and are performed without the visual confirmation of the cells processed, which may lead to an incorrect gating strategy. Recently, a novel image cytometry system (Cellometer) has been developed by Nexcelom Bioscience LLC (Lawrence, MA) for automated cell concentration and viability measurement using bright-field and fluorescent imaging methods. The image cytometer is capable of capturing bright-field and fluorescent images and generates fluorescence intensity data of each analyzed cell. The system can perform gating operations such as fluorescence intensity or cell size similar to flow cytometry on the analyzed cell population. The ability to visually observe the gated cell population allows the elimination of data uncertainties generated using flow cytometry. Here we report, using an enzymatic vitality and viability stain, Calcein AM and propidium iodide, that image cytometry allows for a visual confirmation that the population of cells gated using flow analysis is indeed the population of interest. The image cytometry method offers not only a direct method for performing fluorescence cell-based assays, but also may be utilized as a complementary tool to flow cytometers for aiding the analysis of more complex samples.