Recently I found these weird grey spheres in my cell culture. They are semitransparent very round balls floating above the cells, light grey to dark grey. The big ones are as big as a cell, seemed to have a thin membrane. They often attach on cell debris floating in the dish, usually one piece of debris adhere to one sphere. There are swimming black and white dots in some big spheres. The cells grow slower after these spheres appear.
Are they some kinds of microorganism？How to deal with them?
I’m not sure what it could be, but it definitely looks like a cell.
To confirm that, I would take a sample of the cell culture and stain it with trypan blue. Then, take a look under the microscope. If the gray spheres doesn’t stain and they keep their refringency, your culture will be probably contaminated.
Do you think their number increased over time? Unless their ratio in regard of your cultured cell of interest is high, it shouldn’t make your cells grow slower.
I’m not sure what it could be, but it definitely looks like a cell.
To confirm that, I would take a sample of the cell culture and stain it with trypan blue. Then, take a look under the microscope. If the gray spheres doesn’t stain and they keep their refringency, your culture will be probably contaminated.
Do you think their number increased over time? Unless their ratio in regard of your cultured cell of interest is high, it shouldn’t make your cells grow slower.
It may be a dead or dying cells. They will not stay attached to plate when not healthy.
Are your tissue culture cells doubling ok? (Hek, HeLa.. ect) Doubling well?
If not:
Could be a possability of mycoplasma contamination, if too many cells are not growing well.
Or something in your complete medium is went off, like L-Glut, or something like this.
Or inucbator is dry, or out of CO2.
Trypan Blue exclusion dye will tell if it is a dead cell or not, but not why it died.
Best wishes,
Thank you for all the answers!! I'm not quite so sure that they are dead cells cause they are sooooo round, perfectly sphere, and I never saw dead cells look like that……the refraction looks very different from cell (I think cells' membrane are brighter?)and there are swimming dots in it. After digestion and re-suspension, these spheres break under the force of pipette and shrink into dark small irregular particles (black things in the last picture), the contents leak out of it and make cell culture dirty, full of very small black dots. I attach more pictures. In these pictures I circled a dead floating cell and a weird sphere I said attached to it.
Rui Zhang, I have the same problem! For me, I think that these are slow growing intracellular bacteria. They thrive when the culture health is not good and many cells are dying which increases the burden load of proinflamatory cytokines and stress leading to more cell death and more for the bacteria to grow. You can see prominent dots on/in intact cells as well (check your picture and your cells, you can change the focus a tiny bit and you can tell that these prominent dots are out of focus vs other parts of the cell). It helps if you keep the culture healthy and do extensive wash. Also, leaving cell come close to 100% confluence will allow the dots to spread to other cells very quickly.
I don't use antibiotic for cell culture, and this is the only thing that I find contaminating my cells. The problem is that most cells in my lab has this sucker. I am trying to treat with a cocktail made for general bacteria contamination.
I think I have the same problem with my cell cultures! Did you find what it was and from where it was coming from?
- Badges
- Science topic