Maintaining cell lines in culture, under optimal growth conditions, is essential for production of many biological drugs. The overall health of the culture is generally assessed by the determination of both cell concentration and percentage of viable cells.
Many cell culture facilities, growing cells in bioreactors or flask cultures, use the standard manual trypan blue vital dye-exclusion cell-viability assay. Viable cells, which have an intact plasma membrane, exclude the trypan blue stain, whereas nonviable cells have a permeable cell membrane and stain dark blue.
The manual method requires that an operator be present, using a hemacytometer and light microscope to identify and count both the stained and unstained cells. The total cell count and percentage viability is then calculated.
This manual technique has significant limitations. It is both time-consuming and labor-intensive. Variation in results can also be significant among users analyzing the same cell sample due to the subjective nature of the determination, or to pipetting or mixing errors.
In addition, only several hundred cells are generally counted, which means statistical confidence is low. This variability may contribute to an unstable manufacturing process.
An automated cell counting process removes the variability between operators and frees them for other tasks. This tutorial will describe the key steps of a validation study conducted by a large biopharmaceutical company changing from a manual counting process to an automated counting process. Beckman Coulter Life Sciences’ (BEC) Vi-CELL XR was the automated cell viability analyzer (automated cell counter) used in the study.