[Histonet] PFA Fixed tissue not sticking to slides?

[jenny sandy]

Dear HistoFolks,

Has anyone had experience with cryo-sectioned tissue that is PFA fixed not adhering to slides?

The tissue is rabbit cornea culture, 4% PFA fixed O/N, then run through 20% sucrose gradient, then frozen in OCT.

We think that the PFA fix is much longer than needed for a tissue this thin, and were going to try 2 hr fix. Would over-fixation cause the section to not adhere?  

The PFA/Sucrose fixation really improves the morphology and the IHC stains that we have run so far.

Thank you in advance for your help.

Jennifer Eveleth