Cryosphere Discord server, Chemical Fixation vs. Vitrification
Posted: Sat Nov 15, 2025 12:36 pm
Becca Ziegler and Max Marty hosted a discussion on the Cryosphere Discord server on the topic of Chemical Fixation vs. Vitrification
https://www.youtube.com/watch?v=gvu8P9D6p0g
There was really only one technical detail that I think didn't get enough attention. They both agreed that perfusion is typically not very good and that all cases are less than ideal because of laws that force delays. Aschwin prefers cryoprotectant because it can pull water out of the tissue and potentially gradually open up some of those capillary beds that were having trouble getting perfused. Fine. But that doesn't really solve the problem. You will still (nearly?) always end up with some areas that still don't get perfused well. In the vast majority of cases (I think probably all cases), you will end up with ice in the tissue, and many cases are straight frozen for logistical reasons. This is absolutely abhorrent. Why is this tolerated?
I saw mention in the video of some paper that will claim that ice damage isn't that bad. I'm very skeptical. Even if the ice grows extracellularly, it will expand, crush, and smear the remaining tissue with shearing forces between 25,000 and 114,000 psi. That's some serious mortar and pestle action. The original structure does not seem at all inferable after that. This is my objection to cryonics and why I keep making strong statements about it.
I will also reiterate that no mainstream scientist would use cryoprotection to preserve brain structure. And this is even under ideal conditions with no ice.
https://www.youtube.com/watch?v=gvu8P9D6p0g
There was really only one technical detail that I think didn't get enough attention. They both agreed that perfusion is typically not very good and that all cases are less than ideal because of laws that force delays. Aschwin prefers cryoprotectant because it can pull water out of the tissue and potentially gradually open up some of those capillary beds that were having trouble getting perfused. Fine. But that doesn't really solve the problem. You will still (nearly?) always end up with some areas that still don't get perfused well. In the vast majority of cases (I think probably all cases), you will end up with ice in the tissue, and many cases are straight frozen for logistical reasons. This is absolutely abhorrent. Why is this tolerated?
I saw mention in the video of some paper that will claim that ice damage isn't that bad. I'm very skeptical. Even if the ice grows extracellularly, it will expand, crush, and smear the remaining tissue with shearing forces between 25,000 and 114,000 psi. That's some serious mortar and pestle action. The original structure does not seem at all inferable after that. This is my objection to cryonics and why I keep making strong statements about it.
I will also reiterate that no mainstream scientist would use cryoprotection to preserve brain structure. And this is even under ideal conditions with no ice.