21
Overview
A
A
2 The Measurement Procedure
The determination of the number of viable cells (cells/mL) and viability of cell suspensions (the percentage
of viable cells from the total cell sample) is a fully automated, standardized procedure based on the Trypan
Blue Exclusion Method. A defined volume of Trypan Blue is added by the syringe to the Cedex Sample Cup
containing the cell suspension. The cell suspension and dye are optimally mixed between the syringe and Cedex
Sample Cup by controlled pump actions and then incubated for exactly the same amount of time for each
measurement. This minimizes effects on the viability measurements that might be caused by the toxicity of the
Trypan Blue.
After the incubation period, the stained cell suspension in the syringe is then transported in one portion via the
capillary tubes and the 8-way valve into the flow chamber, which is scanned by the scanner. The scanned image
of the flow chamber is then divided into smaller images for evaluation.
Once the measurement procedure is completed, the Liquid Management system automatically performs a
cleaning routine. It is only possible to start a new measurement after the cleaning routine has finished.
The Trypan Blue Exclusion Method
The Trypan Blue Exclusion Method is based on the principle that viable cells will not take up the dye, while
dead or dying cells have a compromised membrane that allows for the up take of the dye. Thus, dead cells appear
darkly stained.
Trypan Blue has a greater affinity for serum proteins than cellular proteins. If the image has a dark background
due to high quantities of stained serum proteins, centrifuge the cell sample and resuspend it in a protein-free
medium or physiological saline solution prior to counting.
The Measurement Procedure
To Next Page
Loading...