Week 5- Oops…I did it again

Anita M -

The original plan for this week was to repeat the experiment from last week. So we started to do that, but on the second step (transfecting the HEK cells with the GRASP55 plasmid), we experienced the same phenomenon as last time. Cells were peeling off the plate and dying in clumps. We originally hypothesized that this was happening because the cells were too confluent. However, we only put 500,000 cells in each well this time and experienced the same result.
This prompted us to take a deeper look into our protocol and we determined that the cells were being left without media (a solution that contains nutrients for the cells) for too long during plasmid transfection. To combat this, we are going to make some technical modifications to our process. Unfortunately though, this does mean we have to restart the experiment next week.
Attached are some pictures of my cells pre-transfection (top) and post-transfection (bottom). As you can see the cells in the image on top are not as “crowded” as the picture of cells in my previous post, meaning these living cells were much less confluent, which is a good sign. This means we can continue to plate around 500,000 cells per well.
Furthermore, the bottom image shows the cells clumped together and “shriveled,” which is how we can tell that the cells are dead. The cells in the bottom image are a bit difficult to see, so I encourage turning up your brightness to get a better view.

This again is quite an unfortunate series of events, but research is all about figuring out how to keep moving forward despite encountering obstacles, so we’ll just try again!

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    shriya_s
    Hi Anita, I love your attitude about this difficulty! If you don't mind, can you elaborate on the "technical modifications" you will make to your protocol to account for the cells peeling of the plate and dying in clumps?
    anita_m
    Hi Shriya, Of course I can, thanks for asking! By technical modifications I mean more procedural modifications. So the plated cells have media (a solution that contains nutrients for the cells) with 10% antibiotics. Once the plasmid is added, we changed the cells to be in 2% antibiotic media. In between changing the media, we washed the cells with a buffer solution that is nutrient-less. In the future, we are going to skip the buffer solution step so the cells aren't without media for too long. Skipping the buffer solution wash doesn't effect the plasmids' ability to enter the cells, but it could take longer for the process to happen, so we may just have to wait a bit longer before taking the plasmids out. Other than that, I'm also going to make sure to work just a bit quicker to make sure the cells aren't without media for too long.

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