In Vitro Cell Culture: Medium Change and Cell Passaging

The first step in studying diseases is their in vitro approach in the laboratory, aimed at reproducing what is observed in nature but on a small scale at the cellular or tissue level grown in plates or other laboratory instruments. 

To maintain cells in culture, a series of parameters must be controlled, such as the level of humidity and CO2 to which they are exposed, the culture medium used, and the rate of medium changes and cell passaging.

Strategies for Cell Viability

Cells require nutrients to grow, which are usually found in the culture medium. However, as the seeded cells increase in number, nutrients become scarce and the space in the plate diminishes, limiting their development. 

To prevent them from running out of food and space to grow, periodic medium changes and cell passaging are established.

Protocol for Medium Changes and Cell Passaging

The protocol for these medium changes and cell passaging varies slightly depending on the cell type but generally involves the following steps: 

• Introduce the cell suspension into a suitable centrifuge tube.
• Centrifuge for approximately 5 minutes at 100g and at room temperature. To accommodate these centrifugation conditions, the Biocen 22 R centrifuge can be used. It is recommended to consider environmental conditions and activate temperature control if necessary. The Biocen 22 R is distinguished as a refrigerated equipment, perfect for applications requiring maintaining samples at controlled temperatures during the centrifugation process.
• Remove and discard the supernatant containing the old medium.
• Perform a couple of washes with a new medium, repeating steps 2 and 3.
• Add the desired volume of the new medium (this is the “medium change”).
• Count the cells and seed them into new plates (this is the “cell passaging”).
• Incubate the cells until the next passage.

This simple process, which usually takes no more than 30 minutes, is essential for the proper development of cell cultures and is used not only in clinical research but also in other equally important applications, such as maintaining cultures for pharmaceutical production.