Fresh frozen spinal cord cracked and shattered in the center

Thanks for the details!
Glad to hear dry ice works for you.
I’ve done the isopentane mostly because it is recommended for fastest freezing and maintenance of morphology. Also, it’s the method recommended by Visium (10x). If it’s good enough for that, I figure it good enough for anything. 10x has great videos on the freezing and embedding process

https://pages.10xgenomics.com/sup-how-to-visium-tissue-prep.html?wchannelid=92q73hscm6&wmediaid=20jm5uauab

Do you have catalog numbers on those metal molds?

For storing blocks, this is what I’m using

The idea came from here:

For slide storage, I’ve even gone a little over the top:
I put slides in single-shot slide boxes with silica desiccant packets and vacuum sealed

In this way, I have no concerns about long-term stability and quality of the tissue. This is for fresh tissue. For PFA fixed with sucrose, I don’t do the vacuum, but I do the desiccant.