One concern about chemical fixation as a low cost alternative to cryonics is that current fixatives may not be able to permanently fix all biomolecules that are important to preserve the identity of the person. A related concern is that postmortem delays may not permit adequate perfusion of the brain, resulting in pockets of decomposed tissue. On this issue, biostasis at cryogenic temperatures (cryonics) has a distinct advantage because extreme cold will also preserve tissues that were not, or were poorly, penetrated by the cryoprotectant agent.
But even if cryoprotectant toxicity will be overcome to enable reversible vitrification of humans, the procedures of cryoprotectant perfusion, cryogenic cooldown, long term care, rewarming, and resuscitation may often involve (unintended) imperfections that will require advanced cell repair technologies for successful resuscitation.
Perhaps those same advanced technologies could produce a form of biostasis that avoids the crude consequences of contemporary chemical fixation by making precise modifications within and between cells to arrest metabolism and decomposition.
Looking for discussion of this idea, Brian Wowk pointed this writer to Eric Drexler who envisioned such a form of warm biostasis in Engines of Creation. In chapter 7 (section 5) Drexler calls this form of warm biostasis “anesthesia plus:”
To see how one approach would work, imagine that the blood stream carries simple molecular devices to tissues, where they enter the cells. There they block the molecular machinery of metabolism – in the brain and elsewhere – and tie structures together with stabilizing cross-links. Other molecular devices then move in, displacing water and packing themselves solidly around the molecules of the cell. These steps stop metabolism and preserve cell structures.
This procedure would produce a state in which the person will appear to be dead (and warm) for all practical purposes:
If a patient in this condition were turned over to a present-day physician ignorant of the capabilities of cell repair machines, the consequences would likely be grim. Seeing no signs of life, the physician would likely conclude that the patient was dead, and then would make this judgment a reality by “prescribing” an autopsy, followed by burial or burning.
Such a form of warm biostasis would not only produce a true molecular alternative to cryonics, it would also enable long-duration space travel and could be employed as a means to provide trauma care in emergency situations. These kind of applications of molecular nanotechnology are extremely advanced and, as a result, literature, either fiction or non-fiction, about them is virtually non-existent. It seems that the first rigorous treatment of cellular and whole-body warm biostasis will be published in Robert Freitas’ Nanomedicine Volume IIB and Nanomedicine Volume III (personal correspondence).
Perhaps the future of biostasis will be an advanced form of chemical fixation after all.