Automate Centrifugation for Cell Washing

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HT4000A: Cell washing automation

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Centrifugation is used for the separation of fluids according to their density. Separation is achieved by spinning a vessel containing the fluid at a certain speed; the centrifugal force pushes the substances with the highest density to the outside of the vessel. Centrifuges are present in most laboratories from academic to research and are used for different biological purposes: to purify cells, subcellular organelles or different kinds of macromolecules (such as proteins and nucleic acids) but also to remove dead cells and cell debris.

Centrifugation step is usually just a part of a more complex sample preparation protocol that involves other collateral events as well as the adding of buffers/reagents. These reagents for example can be added to the whole sample before the centrifugation to allow the precipitation of some macromolecules and the consequent sample stratification or to modify cell properties or cell vitality. In other cases, buffers can be added after the centrifugation to derivatize the supernatant or to re-suspend the pellet in a different medium.

The manual handling of the centrifugation step and of these related events can be tedious and error-prone. That’s why the automation of these procedures can be fundamental for many sample preparation protocols.

The automation can be not limited to these phases but it can be extended to all the other steps of the sample preparation.

A typical example can involve the manipulation of peripheral blood to isolate - for research purpose - leucocytes marked with fluorochrome-conjugated antibodies. In this case the markers are added to the whole blood specimen, then the adding of a lysing solution for a defined time allows the erythrolysis to occur (with minimal effect on leukocytes ). A centrifugation step at a proper force allows the precipitation of the white blood cells that can be washed and then resuspended in a proper buffer to be furtherly analyzed for example by flow cytometry (red cell debris remain in the supernatant). The whole procedure can be automated by a single tailored sample prep workstation.

The application described in this post refers to a generic laboratory equipment used to sampling and preparing liquid samples for different applications and it is not designed and intended to be used as IVD devices.