Histology/Paraffin Embedding - Protocols and Trouble shooting (Feb/20/2009 )

I have been culturing cells in a 3-D gel and after fixing the gels in formalin, I have attempted to embed them in paraffin. When I section the paraffin, however, a common problem is that paraffin surrounding the gel is flaky and brittle. As a result, I'm left with a hole in the section where my gel should be.

I think the problem has to do with the embedding process. During embedding the gels are much cooler than the paraffin and as a result, when I initially place the gels into the paraffin, I think a layer of amorphous paraffin forms around the gel. (If you look at the finished paraffin block, the areas surrounding the gel are white paraffin).

My question is this: Is there any way to reform that amorphous region without removing/damaging the gel inside? For instance, could I heat the block up to 60 deg C and try to re-from those regions??

Speak to your histology core (the people who can adjust things to suit paraffin embedding). They are the ones who could really help you.

maybe it is because your gel only has a few % of matrix that makes it fragile? I dont know if cryosection after OCT embedding, or plastic resin will help.