Hello all, I am culturing MCF7 cells that are in DMEM/High Glucose media. I split these cells once and the next day noticed these "gold foil"-like residues in the media plate. They seem to be attaching and growing with the cells because every time I wash the plate with DPBS, they go away. Everything in the culture room and culture hood have been cleaned with sterilizers. New bottles of media, DPBS, and trypsin are used. However, once new media is added and the plate is placed back in the incubator, they seem to grow back again. Are these contaminates? I appreciate all feedback!
This could be contamination but could also be some protein/salt precipitates in the media. You can check if there are any precipitates on the bottom of the bottle with media. You can also add media to a clean new dish without cells and check under the microscope if those particles are present. Also, do they see to grow if you leave the cells for 2-3 days without changing the media (if so, this is most likely contamination)?
Hi Sarah Truong
Looks like some bacterial contamination. If these granules are protein/salt precipitation, they will go out within the next 2/3 passages. If you see similar granules even after fresh passage, you should begin from a fresh lot of cells with newly prepared media.
Dear Sarah!
Most likely, this is not contamination, but a conglomerate of adhered cells that remained after reseeding or insufficient washing. The cells in this conglomerate, like individual cells, can adhere to the substrate and also begin to proliferate. I would not pay much attention to this. If you are concerned about this, try to peptide the cells vigorously on subsequent subculture.
Hello Sarah Truong,
I agree with Dr. Alexandr Chernov. Also, if you see it for yourself, the size of these cells is way larger than what a bacterial cell should be. It seems to be cell clumps that have remained together. I suggest that you prepare a single-cell suspension by gentle pipetting during sub-culturing and washing. Good luck!
Sarah Truong
I am guessing this is coming from your FBS.
My suggestion: Filter your media (0.2um filter) and culture cells with that.
Have you looked at the appearance of the media inside the flask? Does it have the usual shine that media often glitters with? If not then it could be contamination. Whenever I am unsure of the contamination or debris I just spread some of the media (in Bottle as well as from flask) onto the agar plates and incubate at 25 and 37 degrees. Observing after 3-4 days can clear a lot of doubt.
Additionally, my first impression is that it could be the precipitates that are commonly seen in the FBS or clumps of the cells
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