I am getting black tiny swimming dots in cell culture. The cells are mycoplasma free. I have already treated the cells with 1% penstrep and 1% amphotericin B, but could not get rid of it. It comes again and again and stick to the plate and also floating in the media. And when this is happening, it also becomes hard to trypsinize the cells. Generally the cells need 5min to trypsinize, but when this black dots are there, they taking more than 15 min to trypsinize, sometimes they are too sticky. Would you please help me to get rid of this problem?
Dear Shayantani Chakraborty,
most liekly some bacteria (coccus) or yeast. Make sure to replace everything (media, PBS, antibiotics, additives, etc) and clean your bench and your fridge where you store. And I mean decontamination according to manufacturers description in terms of concentration and time and not UV-light. Advice researchers to wash hands before handling cells. Thaw fresh stock of cells and you should be fine. Concerning trypsination - lower cells numbers (which you get when contamination is present) might explain your observation.
Good luck
Boris
