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One step forward for cryonics, but plenty of work remains
For years, the biostasis world has been waiting for Greg Fahy, the cryobiologist behind 21st Century Medicine’s flagship “ice-free” cryopreservation chemistry, to show something very basic: what a human brain looks like after a modern cryonics-style procedure. Because without that kind of evidence, the whole project rests on an assumption: that the brain’s information-bearing structure is preserved well enough that future technology could, in principle, recover the person.
One of the main enemies in cryopreservation is ice. Ice crystals expand as they form and can shred delicate tissue. The only place ice is truly harmless is in the emojis often used to symbolize cryonics - snowflakes, frozen faces, blocks of ice. They get the idea across instantly, even if they’re technically wrong. Cryonics, after all, is full of tradeoffs.
Among cryonics proponents, the leading strategy to avoid ice formation is vitrification: instead of freezing into ice, the tissue is loaded with a very concentrated cryoprotectant solution and cooled in a way that makes it solidify into something more like a glass than a crystal-filled block. “Glass-like” here doesn’t mean literal glass, it means a solid without ice crystals.
There’s also an older, parallel approach that has attracted attention in the brain-preservation world: aldehyde fixation. Aldehydes are chemicals that “lock” tissue in place by cross-linking proteins (like setting jelly). It’s excellent for preserving structure for microscopy, but it’s also obviously fatal by today’s medical standards, which is why vitrification without prior fixation has remained the more relevant target for “mainstream” cryonics.
This is the context in which Fahy’s new paper lands. After years of mostly indirect evidence, this was the moment when the field finally had to look at the results up close in a human case. And it could easily have gone the other way: that, once examined, showed a brain wrecked by ice, dehydration, or other microscopic damage. The kind of result that would have pushed cryonics back.
Instead, Fahy’s preprint turns out to be something more interesting: a genuine step forward. Albeit one that still leaves the hardest questions open.
