How long are cells viable on ice - (Jul/21/2012 )

Hi!
Sorry if this question is rather stupid, but I'm very new to cell culture.
Yesterday I had to split some HEK293T cells for the first time. I trypsinated them, diluted with fresh media, spun them down and resuspended the cells in 1.5mL fresh media.
Then I had to leave the lab unintentionally for my supervisor wanted me to join some stupid lecture. He said I can put the cells on ice during this time, and so I did...

Now the question I have - how long is it possible to store suspended cells on ice before they die or take any damage? I left the lab for about 2 hours, so that's pretty long in my opinion. When I got back the cells were like a dense pellet in the falcon tube. When seeded to new culture flasks they looked okay, but I'm nervous anyway... so do I have to expect a mess on monday or will my cells be fine?!
Thanks!

I wouldn't worry, your cells will be fine

The pellet you saw is normal, as the cells will settle out of the media over time. And I don't believe that being on ice for that short a period will have any impact on viability, and if there is some impact it will be minimal.

OK, thanks. Fortunately, my cells looked quite nice today