Passaging cells refers to the process of transferring cells from one culture vessel to another in order to maintain or expand the cell population. This is typically done with cells grown in culture, such as those used in research or biomanufacturing. Here are the general steps involved in passaging cells:
- Preparation: Before starting, make sure you have all the necessary materials and reagents, including culture vessels, media, and trypsin. It’s also important to work in a sterile environment to prevent contamination.
- Remove old media: First, remove the old media from the culture vessel containing the cells to be passaged. This can be done by gently aspirating the media with a pipette.
- Wash cells: Next, wash the cells with a balanced salt solution, such as phosphate-buffered saline (PBS), to remove any remaining serum or media components.
- Add trypsin: Add trypsin to the cells, which will detach the cells from the culture vessel surface. The amount of trypsin and incubation time will depend on the specific cell type and culture conditions.
- Neutralize trypsin: Once the cells have detached, add fresh media to the culture vessel to neutralize the trypsin and stop the enzymatic reaction.
- Collect cells: Collect the cells by gently scraping the culture vessel or by pipetting up and down to create a cell suspension.
- Transfer cells: Transfer the cell suspension to a new culture vessel containing fresh media, and make sure to adjust the cell density as needed.
- Culture cells: Place the new culture vessel containing the cells in the incubator and allow them to grow and expand.
It’s important to note that the exact passaging protocol will depend on the specific cell type and culture conditions. It’s also important to avoid overpassaging, as this can lead to changes in cell behavior and phenotype.