A Small Breakthrough in Freezing People (and Zebra Fish) for Science and Space Travel

Cryogenics, the idea that a human body can have metabolic activity halted in cold temperature and later revived, has be prevalent in science fiction for decades.

It’s become so prevalent that a pervasive urban legend survives that Walt Disney – who died in 1966 from lung cancer – had himself frozen so that he could be revived at a time when science would allow him to make children happy again.

In science fact, cryogenics  has had great success in preserving human embryos for later implantation.

Embryos can be frozen and later revived with great success. So far, no one is quite sure what the shelf life of a frozen embryo is, but successful pregnancies have resulted from embryos that have been frozen for 13 years, and there is reason to believe that science has reached a point where embryos can be frozen indefinitely without significant damage.

Death by ice crystal

The more complicated the tissue is, the more difficult it is to freeze and revive. In more complicated tissue, ice crystals form and expand when reheated, killing the tissue to which it is attached.

But that may be changing. According to a recent report published in the science journal ACS Nano, a breakthrough in nanotechnology has made it possible to revive zebra fish embryos that have been placed in cryogenic stasis.

Zebra fish embryos have long been a favorite means of study for cryogenic scientists, as they are transparent and it is easy to track the metabolic processes taking place. They are, however, more delicate than human embryos, so reviving them after freezing has proven impossible – until now.

In the new experiments with the zebra fish, the fatal ice crystals have been thwarted by inserting gold nanorods into the tissue to conduct heat from the lasers used to warm up the embryos.

This allows the thaw to happen quickly and evenly before the ice crystals form. And ten percent of the time, the zebra fish survive. The theory is that using this same technique could aid a damage-free de-thawing of human tissue more complicated than the embryonic stage. That’s not anywhere near good enough to allow astronauts to be placed in suspended animation to journey for centuries to other planets, but it’s a tiny little step in that direction.

Embryos in space?

Indeed, one of the lures of cryogenics has been the idea of freezing people for decades or even centuries as they travel to distant worlds.

Since we still haven’t figured out how to freeze and revive a grown human being, like Walt Disney, some have suggested sending frozen embryos into the final frontier. Little thought has been given by would-be proponents to the mothers’ wombs necessary to help the little creatures move past the embryonic stage.

Still, as the Disney legend illustrates, fascination with cryogenic freezing has been part of the collective consciousness for a very long time.

If it were possible to go into stasis until science came up with a cure for cancer, we’d very likely see warehouses of frozen future patients dotting the landscape. There are also those who are perfectly health that would still like to go into deep freeze to see what the world will be like a couple of centuries from now.

And, of course, there are those who want to set foot on a world with a distant sun. Given that our closest neighbor outside the Solar System is 4.3 light years away, it would take hundreds of thousands of years to get there at the speed of current space travel technology.

That means you either need solid cryogenic technology or a really, really long in-flight movie.

If only Walt Disney were still around.

(Photo of researchers at the Hussman Institute for Human Genomics, University of Miami, next to a cryogenic freezer that holds DNA samples in the genetics lab where they did research that discovered the cause of retinitis pigmentosa, a form of blindness in February 2011, by Joe Raedle/Getty Images.)


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