GFP, PBS and warmth

Tom Anderson via (by ucgatan from
Mon Feb 4 21:10:07 EST 2008

On Sat, 2 Feb 2008, Tom Anderson wrote:

> Can anyone tell me what my GFP-expressing cells will look like having
> been fixed in formaldehyde and then incubated in PBS at 37 degrees for
> twelve hours?

Well, i found out: they're fine. The cells themselves look a bit unhappy,
but i have a biological explanation for that, based on their being exposed
to 240 volts of electric field twelve hours earlier.

However ...

> Note to self: in future, when doing a timecourse experiment, put the
> coverslips for each timepoint in separate four-well dishes.

There was another coverslip in another well, which was sat there in medium
during fixation and washing of the first coverslip, and then waited
another twelve hours before being fixed. Those cells are absolutely
destroyed; collapsed, shrunken, warped, unholy travesties. My first
thought on seeing them was to wonder how i was going to be able to burn
glass, and where i was going to find a priest at this time of night.

So, kids: formaldehyde is powerful stuff! Just having a 4% solution
sitting near your cells for ten minutes is enough to do them over proper.
So don't do that.


Tom Anderson, MRC Laboratory for Molecular Cell Biology, UCL, London WC1E 6BT
(t) +44 (20) 76797264   (f) +44 (20) 76797805   (e) thomas.anderson from

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