Countess 3 FL Automated Cell Counter

In addition to counting cells, the fluorescence capabilities of the Countess 3 FL instrument are often used to assess cell viability, apoptosis, transfection efficiency, and fluorescent protein expression. But the applications extend to any cellular parameters that are autofluorescent or can be labeled using fluorescent dyes. You’ll find data illustrating cell culture quality control, CAR-T cell screening, CRISPR-Cas9 editing efficiency, and other fluorescence applications in Sample Data.

Cell viability. Assessing cell viability is a key step in daily cell culture and is required for accurate and efficient downstream processing. The Countess 3 FL fluorescence options offer a sensitive and specific viability check that can be performed quickly and easily prior to downstream sample analysis.

Although trypan blue is widely used for viability assessment in brightfield cell counting, it can alter cell morphology in certain cases. For example, when dead mouse PBMCs are stained with trypan blue, they can expand and sink to a different focal plane than live cells, complicating accurate detection and counting. As a fluorescence alternative, Invitrogen ReadyCount Green/Red Viability Stain contains acridine orange and propidium iodide (AO/PI) in an optimized combination. Fluorescent staining provides great sensitivity and greater specificity of live/dead status in a mixed cell population without altering the morphology of the cell.

The Countess 3 FL instrument has two optional fluorescence channels, which will detect fluorescent colors determined by the insertion of individual light cubes. With 14 interchangeable light cubes to choose from, the Countess 3 FL instrument is not limited to detection of cells expressing GFP and RFP.

Suppose you are interested in measuring both apoptosis and viability of cells in a population. You can use an apoptosis indicator that measures caspase activation, such as CellEvent Caspase-3/7 Green Detection Reagent along with the EVOS GFP 2.0 light cube. Additionally, use a viability dye such as SYTOX Red Dead Cell Stain with the EVOS Cy5 2.0 light cube to measure dead cells that have progressed past apoptosis. This staining combination, along with the two EVOS light cubes, offers a fast and simple multiplex method to obtain apoptosis and viability data.

Fluorescence staining can provide rich data on cells, even in heterogeneous samples, but can be difficult to optimize. Invitrogen ReadyCount reagents are bench stable fluorescent stains that are pre-optimized for use with Countess 3 Automated Cell Counters.