Trypsinisation

Trypsinization is the process of cell dissociation using trypsin, a proteolytic enzyme which breaks down proteins, to dissociate adherent cells from the vessel in which they are being cultured. When added to a cell culture, trypsin breaks down the proteins which enable the cells to adhere to the vessel. Trypsinization is often used to passage cells to a new vessel. When trypsinization process is complete the cells will be in suspension and appear rounded.

For experimental purposes, cells are often cultivated in containers that take the form of plastic flasks or plates. In such flasks, cells are provided with growth medium comprising the essential nutrients required for proliferation, and the cells adhere to the container and each other as they grow.

This process of cell culture or tissue culture requires a method to dissociate the cells from the container and each other. Trypsin, an enzyme commonly found in the digestive tract, can be used to "digest" the proteins that facilitate adhesion to the container and between cells. Most commercially available trypsin is of porcine origin, while alternate reagents formulated from animal origin-free recombinant proteins enable simpler workflows and are gentler on cells.

Once cells have detached from their container it is necessary to deactivate the trypsin, unless the trypsin is synthetic, as cell surface proteins will also be cleaved over time and this will affect cell functioning. Trypsin is inhibited by serum and the divalent cations calcium and magnesium, so serum is usually added to the container once cells have detached - this can be confirmed by observation under a microscope.

Trypsinization is often done to permit passage of the cells to a new container, observation for experimentation, or reduction of the degree of confluency in the flask by removal of a percentage of the cells.

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