Fluorescence lifetime imaging microscopy (FLIM) techniques are widely used in auto-fluorescence imaging to investigate dynamic metabolic states of the cells. Traditional FLIM imaging requires the cells to adhere to the coverslip to collect enough photons for FLIM data processing. Such conditions pose challenges to non-adherent cells, such as acute myeloid leukemia (AML) cells, because of cell motility. We developed a proto-type micro cell trapping array (MCTA) to immobilize cells in picoliter-size wells with location references. The array keeps non-adherent cells in referenced well locations, allows treatment on stage and re-imaging after time for ultimate cell segmentation analysis. Individual wells are analyzed by a pixel-based region-of-interest (ROI) to analyze cellular redox states. This single well trapping and analysis method allows to isolate treatment responses of a small number of cells, compare their range and predict early effect, which may have clinical applications in the context of cancer aggressiveness and treatment outcomes. We expanded the common intensity-based assay for cellular redox state by a Fluorescence Lifetime measurement, NAD(P)H-a2%, serving as an alternative metric. The new assay is flexible and can be applied to other non-adherent cell lines, expanding FLIM applications in both research and the clinic.
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