Cryonics Posts — 2026-04-24 Nectome Meeting Outgrowth

Two Substack posts drafted from a meeting with Nectome (Aurelia, Charlie, Jasmine) in Portland on 2026-04-23. Nectome uses aldehyde-stabilized cryopreservation (ASC) for MAiD patients and has a March 2026 bioRxiv preprint extending the protocol. They are bottlenecked on writing / comms, not engineering, so these posts are also useful to them.

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Two posts

Post 1 — Why are humans (not) solid?

Core question: why is an egg easy to turn into a solid but a human body isn't, and why does aldehyde fixation change that?

Aurelia's framing (from meeting): eggs are mostly protein, so they set easily. Human tissue is much messier. Aldehyde fixation might be "a little thing that causes it to all turn solid" by cross-linking proteins. Possibly a lot of cell death is from related chemistry.

Folder: post-1-why-humans-solid/

Post 2 — Bloodflow and scan quality

Core question: why is brain preservation bottlenecked on perfusion (capillary-level bloodflow) rather than on the cryoprotectant itself, and why does scan modality matter so much for evaluating quality?

Aurelia's framing (from meeting): - Pressure → large-pipe vs small-pipe flow (Poiseuille-type) means most flow bypasses capillaries - Brain capillaries are so small that RBCs have to deform — small size changes kill perfusion - Ischemia collapses capillaries by ~90% in volume ("no-reflow") - Brain swelling in skull bursts capillaries; drugs can safely shrink a living brain ~10% - Standard cryoprotectants don't solve the perfusion problem - Main arteries can silently block mid-procedure — surface looks fine - CT scans and optical microscopy can look fine while electron microscopy reveals terrible preservation at the ultrastructural level - There are "~19 factors" that affect ischemia; nobody knows how to control all of them - Cooling the skin is not cooling the brain; effective brain cooling has to go through circulation

Folder: post-2-bloodflow-scan-quality/

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