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Scope 45 - Flow Cytometry - shedding light on the unknown

22 July 2011

Flow cytometry is a fundamental tool used by every research group at the Malaghan Institute. 

Using flow cytometry a scientist is able to take a tube of invisible cells and in the blink of an eye, know exactly what it contains.  Whether it be the study of a whole lymph node, or a newly discovered cell type, the knowledge gained from using this technology is invaluable.  So what is flow cytometry and how does it work?

If we use the analogy of a bag of jellybeans to describe the cells present in a lymph node, then each of the different coloured lollies would represent a different cell type – black jellybeans could be T cells, red jellybeans, dendritic cells, and so on.  If that bag contained thousands of jellybeans, just as lymph nodes contains thousands of cells, then the process of counting them and working out how many of each colour were present would be an arduous process. However, a flow cytometer can count and identify each cell type at the extraordinary rate of up to 20,000 cells per second!

Furthermore, if a scientist were only interested in one particular flavour of jellybeans then a more advanced cytometer called a cell sorter could be used to separate them away from all the others at the same high speeds. 

Unlike jellybeans however, cells are not naturally coloured, so fluorescent dyes are first attached to the cells via specific antibodies to help the scientist mark the cells they are interested in. When placed into the flow cytometer the dyes are excited by laser beams, which give out different signals that are picked up by detectors and translated into useful information about the size and identity of the cells present.

With recent advances in the number of characteristics that can be simultaneously analysed per sample, the applications of flow cytometry are limited only by the user's imagination.