Fig. 2. Demonstration of VIFFI flow cytometry.

Immortalized human T lymphocyte cells (Jurkat) and E. gracilis cells are used for all cases. a Fluorescence images of the cells at rest obtained by conventional fluorescence microscopy. The images are representatives of >10 images of cells obtained under identical imaging conditions. b Fluorescence images of the cells in a 1-m s⁻¹ flow obtained by IFC without VIFFI with an exposure time of 0.3 µs. c Fluorescence images of the cells in a 1-m s⁻¹ flow obtained by IFC without VIFFI with an exposure time of 340 µs. d Fluorescence images of the cells in a 1-m s⁻¹ flow obtained by IFC with VIFFI with an exposure time of 340 µs. Green: nucleus for Jurkat cells (stained by SYTO16), lipids for E. gracilis cells (stained by BODIPY505/515). Magenta: cytoplasm for Jurkat cells (stained by CellTracker Red), chlorophyll for E. gracilis cells (autofluorescence). It is clear from the comparison of the fluorescence images that VIFFI significantly improved the spatial resolution and SNR in the images without sacrificing the throughput. Scale bars: 10 µm.