Occasionally, cells from the freezer won’t grow. This isn’t your fault or the fault of the student who previously cryopreserved the cells. After the cells have been in the growth media for 48 hours, you will know through observation if your cells are growing or not.

Identifying healthy, growing cells is fairly simple. Healthy cells have similar morphology (are fairly regular in shape), are confluent (growing across the entirety of the plate), and won’t have excessive vacuolation (white spots).

We’ve included a few images here of healthy cells for you to get an idea of what they look like.

Healthy Cells Examples
| Confluent Healthy Cells at 100X Magnification
| Confluent Healthy Cells at 250X Magnification

Some common problems you might run into are cells that don’t grow or contamination by fungi or bacteria.

Cell Contamination Examples
| Possible Contamination
| Possible Contamination

If you have happy cells, you can move on to feeding them. If your cells aren’t growing or are unhealthy (for whatever reason), you may need to start a new culture. Talk to the instructor in the lab if you think you might have a problem with your cell growth.

### Learning Objectives:

- 1.3 - Feed cells to maintain life.