Prolong in paraformaldehyde - What's the influence? (Sep/15/2010 )

Dear all:
Recently, I done the cardial perfusion with 4% paraformaldehyde for the mice. After dissecting organs, I stored the mice brain, heart, liver, and kidney in 4% paraformaldehyde in -4C. The optimal duration is 12~18 hours in 4% paraformaldehyde and needed to change to 30% sucrose or PBS with Na-azide. However, I forgot the duration and changed the organs to 30% sucrose after 20 hours in 4% paraformaldehyde. Will the mistake influence the results of further IHC stain or immunofluorescence staining? And how about the longest duration in 4% paraformaldehyde is before I changing organs to 30% sucrose? Thank you!

You should be OK, 18 hours is optimal I guess, but PFA should last up to a few days at least, before it starts to degrade.

bob1 on Thu Sep 16 02:32:11 2010 said:

i leave mice brains for 24 hrs in PFA.