long term human suspended animation

Otherwise known as Cryogenic Suspension, Cryopreservation, or simply as Cryonics, cold is the only known way of reliably inducing a state of stable suspended animation in animal tissues (bearing in mind that 'suspended animation' may be a misnomer if the tissue we're talking about is a steak, but is still correct if we mean a transplantable heart, liver, or tooth). Cool the cells down to the point where molecular and cellular degradation occurs very, very slowly, and the theory is that you can bring someone back. It's a little like the people who fall into freezing lakes and go into hypothermic shock, effectively drowned for minutes at a time, and are then revived - but vastly more complicated.

The main complication is that the human body is approximately 70% water. When water freezes, it forms ice crystals, drawing all the liquid out of the cells to form crystals in the intracellular space. This dehydrates the cells themselves until they are damaged beyond the point of recovery. That's why if you freeze vegetables, and then thaw them out, you usually get that slightly funky thawing liquid coming out as well. The ice crystals inbetween the cells melt into water, but the cells in the vegetables have been damaged too badly to reabsorb the water effectively.

The idea that ice crystals form within cells and burst the cell membranes is a myth, by the way.

When we freeze cells, such as sperm and ova, or very small cell clusters such as zygotes, we get around the ice crystal problem by vibrating the cells as we lower the temperature. This inhibits ice crystal formation, and limits the cell damage. Or, in some cases, we snap-freeze the cells, lowering the temperature so quickly that there is no time for ice crystals to form, and the cells freeze solid.

Neither technique works for entire human bodies or even for smallish organs, never mind entire brains. If that large a cluster of cells is cooled too quickly, the outer layers get significantly colder before the inner layers have caught up, and uneven shrinkage causes problems such as peeling of layers of tissue. Vibrating an entire large cell cluster, such as an organ or entire organism, is impractical using current technology, and may cause tissue damage in itself. Instead, to put a person into that sort of suspended state, we replace the blood with cryoprotectant chemicals - basically biological antifreeze - and cool the body relatively slowly to the desired temperature. The cryoprotectant chemicals prevent ice crystals from forming, and instead the entire cell cluster is vitrified - turned into a very cold, stable, noncrystalline solid with many of the properties of a liquid. This vitrified tissue must be kept within a specific temperature range; too warm, and the tissue is not effectively preserved, too cold and there is a danger of cracking even if no ice crystals have formed.

The problem with that approach, aside form the danger of cracking at very low temperatures, is that most of the known cryoprotectant chemicals are also toxic. The percentage of cryoprotectants in the cell cluster must be carefully controlled and limited during the cooling process to avoid cell and tissue damage, and even more carefully controlled during the thawing process, as the cryoprotectant chemicals are removed form the cell cluster and blood is re-profused through the tissue. Until now, this chemically mediated vitrification process was the most advanced known technique for inducing long term human suspended animation.

However. As of last year (2010) there is a new process being researched. It was developed by Japanese food scientists for preserving sashimi, but has been experimentally applied to the cryonic preservation of teeth (a difficult process, as teeth usually lose viability in a matter of hours) and is exciting a great deal of interest in the potential for cryopreservation of transplantable organs. The basic idea is that an oscillating magnetic field is used to 'vibrate' the tissue during the cooling process, preventing water molecules from aligning to form ice crystals. Once a certain temperature is reached, the water molecules no longer have sufficient energy to line up, and are unable to form ice crystals. The tissue is effectively vitrified without the use of cryprotectant chemicals.

To me, this is a very exciting development. Not only does it show real promise for cryonic preservation and revival of entire organisms (essential for any long term space travel or colonisation mission - who wants chickens, horses, or cattle running around underfoot in the space ship? But on the other end of the trip we'd want them), but it has a significant impact on my intention to stay alive for a very long time. We can already print some organs, and there is very promising research into printing more complex organs using adult stem cells and cartilage frameworks. If I could simply have a spare heart, liver, and a couple've kidneys printed and then stored indefinately in case I need them, that would vastly improve my chances of sticking around in case something terrible (accident, illness, ...) happens. And the potential to suspend and revive entire organisms is a nice little insurance policy in case transplanting new, fresh copies of my own organs isn't going to cut it.

The plan: build a miniature version of the magnetic freezer, and carry out some experiments.

complexity of now

We see the future the way we see the present - linear extrapolation. Humans are very good at linear extrapolation. We're not so good at comprehending exponential growth.

We're also not very good at imagining the future being very much like the now. It's always utopias (Star Trek, ) and dystopias (Transmetropolitan, V For Vendetta, The Handmaid's Tale, ...). What people don't seem to be very good at understanding is that things change massively quickly, but they do so mostly in the background. Star Trek technology looks like magic to us, but to the characters it's commonplace. LCD TVs and smartphones are commonplace to us, but even a generation ago they would have seemed marvellous, and 100 years ago they would have seemed like magic.

We can look back at the last century, and see astounding changes in technology, but we missed most of them as they happened. The big, obvious changes, sure - people noticed the television, the personal computer, the mobile telephone. But who noticed the vast but creeping changes to video displays once we had them? Who noticed the increasing power of satellite telescopes, and the wonder of seeing stars millions of light years away? Things have been getting better by increments, we've been learning more and more by increments, and our global culture has changed by increments to accommodate and surround those changes. But it's very easy to miss that happening.

Compared to 300 years ago, we do live in an utopia. And equally, we live in a dystopia. And compared to life now, life 300 years ago was an utopia - and a dystopia. Everything is relative; it depends what you expect, and what you focus on, and what you value. Real life is more complex than you think.