Aldehyde-Stabilized Cryopreservation, explained.
ASC is the only post-mortem preservation technique that has won a Brain Preservation Foundation prize at the mammalian scale. It permanently forecloses biological revival. It preserves the connectome at the nanometer level.
An informational challenge, not a biological one.
The objective of ASC is not to preserve a living brain. It is to preserve the brain's connectome — its precise synaptic wiring diagram, encoded in the arrangement of 100 trillion connections between 86 billion neurons.
For the purpose of future digital emulation, what matters is not whether the brain can be biologically revived — it is whether the structural information can be read. ASC is optimized for information, not biology. This is the central conceptual move that distinguishes the science from earlier cryonics programmes.
How ASC works.
1. Standby
Upon membership activation, your SST (Standby, Stabilisation & Transport) standby contract is registered with a Tomorrow Biostasis network partner in proximity to your registered location. On-call medical personnel are placed close enough to begin perfusion within the critical post-mortem window.
2. Stabilisation
Immediately following legal pronouncement of death, perfusion begins. The brain is cooled and perfused with a buffered solution to prepare it for chemical fixation. The objective is to halt biological decay without disturbing the structure we are about to preserve.
3. Glutaraldehyde fixation
Glutaraldehyde is perfused through the brain, chemically cross-linking proteins at the molecular level. This permanently fixes the cellular structure — the neural membranes, the synaptic junctions, every spine and cleft — at the moment of preservation. The connectome is locked in place.
4. Vitrification
After chemical fixation, the brain is vitrified and stored below −135°C — the glass transition temperature of water. At this temperature, biological decay is effectively halted. The preserved asset can be held indefinitely.
What the science has actually shown.
The Brain Preservation Foundation (BPF) runs a rigorous, independent verification protocol. To win a BPF prize, the preserved brain must be shown — under electron microscopy — to be indistinguishable from a fresh, living brain, with respect to:
- Synaptic vesicle roundness
- Synaptic cleft spacing
- Membrane integrity across the entire volume
- Myelin sheath preservation
- Overall ultrastructural fidelity
ASC has won BPF prizes in:
The pig brain is the more significant result. A pig brain is comparable in size and complexity to many regions of the human brain, and the 2018 prize demonstrated that ASC scales.
What comes after preservation.
ASC preserves the structure. Reading it — at the resolution required for digital emulation — requires electron microscopy at petavoxel scale, automated tissue sectioning, and reconstruction algorithms that do not yet exist at production scale.
This is the science we are waiting for. We do not have a timeline for it. We have a fiduciary obligation to ensure the preserved connectome is intact when the science arrives.
That is the role of the Patient Care Trust: to hold the asset, in perfect condition, for as long as it takes.