I've never worked with Vero cells but you could investigate a mycoplasma contamination.

Looks to me like the cell density is too low.  I've never worked with Vero cells, so I might be wrong.  Try taking 2 or 3 vials out of the nitrogen and plating them together for a larger density.

I agree with Kerry, the cell density is too low.

It is better to use smaller cell culture vessel for freshly thawed cells. You could try to increase FBS to 20% and put them to incubator with 5% CO2 and wait. Certainly, do not do further passaging until your cells will not be in monolayer (touching to each other).

Hello all,

Thank you very much for your answer. The cells growth came back to normal after I reseeded it into the same flask. So, maybe Vero has some lag if thawed from liquid N2 and perhaps reseeding (using trypsin) can encourage cell division after thawing.

My vero cells have arrived in dry ice so I thawed quickly in water bath and added the cells in T25 flask, it has been now seven days but still not attached. I have used DMEM with 10% FCS heat inactivated, 1% L-glutamine and 1% Penstrep.

However, I will try to added 10% more FCS to the T25 flask and allow to grow for a couple of weeks, changing medium every 3rd day.

Please comment required.

dear Khrisna Putera Buddhiman,

the growth rate of Vero cells is very slow and it might take a week to reach the confluency of 80%. you should freeze the cells with a medium containing FBS 20%, and then thaw the cells with medium containing FBS 20%. this will help the cells grow faster.besides, reseeding in a new flask after thawing(when cells reached 70-80% confluency) can boost the growth of the cells.