Slashdot Mirror
Scientists Have Found a Way To Rapidly Thaw Cryopreserved Tissue Without Damage (sciencealert.com)
schwit1 quotes a report from ScienceAlert: Researchers have developed a technique that allows them to rapidly thaw cryopreserved human and pig samples without damaging the tissue -- a development that could help get rid of organ transplant waiting lists. Cryopreservation is the ability to preserve tissues at liquid nitrogen temperatures for long periods of time and bring them back without damage, and it's something scientists have been dreaming about achieving with large tissue samples and organs for decades. Instead of using convection, the team used nanoparticles to heat tissues at the same rate all at once, which means ice crystals can't form, so they don't get damaged. To do this, the researchers mixed silica-coated iron oxide nanoparticles into a solution and generated uniform heat by applying an external magnetic field. They then warmed up several human and pig tissue samples ranging between 1 and 50 mL, using either their new nanowarming technique and traditional slow warming over ice. Each time, the tissues warmed up with nanoparticles displayed no signs of harm, unlike the control samples. Afterwards, they were able to successfully wash the nanoparticles away from the sample after thawing. The team also tested out the heating in an 80 mL system -- without tissue this time -- and showed that it achieved the same critical warming rates as in the smaller sample sizes, suggesting that the technique is scalable. You can view a video of tissue being thawed out in less than a minute here. The research has been published in Science Translational Medicine.
If only there was something you could click on that would take you somewhere else that had more information.
"The team admits that larger tissue - and even whole organs - will need to have the nanoparticles injected into them, rather than just sitting around them, to achieve the same uniform heating, but it's something they want to try next."
Thawing is great. How are you going to freeze the tissue without damage?
Become an Alaska Wood Frog (alternate article). They survive being frozen almost completely solid for 7 months at a time.
It must have been something you assimilated. . . .
So you need to add something that creates an amorphous solid ice when mixed with water, or at least far smaller ice crystals.
Which is exactly the technique used by some fishes that can survive in the ice :
they secrete some sort of anti-freeze in their bloodstream which prevent big ice crystals to form.
"Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
Actually all the reports are that it tastes like pork, which is also rather explains why the attempts to wean cannibals off of eating humans worked when they provided them with pigs to raise and eat.
At a certain temperature water freezes solid almost instantly, which means its molecules don't have time to rearrange themselves into a crystal lattice. This kinda makes it more fragile but that's not part of this answer. What is part of it is that as the boundary of heat penetrates the frozen object, there is a small war of temperatures. One side is hot fading to cold, the other is cold slowly warming. On the cold side of the boundary ice turns to water, expanding the boundary enough that the water next to the much colder than normal ice can then turn back into ice, much more slowly (comparative to the flash freezing process from before), and form crystals. They aren't large crystals, but human cells aren't large either.
An example of this is having damp fingers after refilling an ice tray and using a paper towel to dry your hand, then grabbing an ice cube and finding that it freezes to your fingertip. Your finger is warm, the thin coating of water on it is at skin temperature, between 65-75 degrees F, but the ice is cold enough to freeze the water on your skin almost instantly and stick to you for a few moments before your body's heat overcomes it and melts the water again.
What the nanoparticles here are doing is warming the entire object at once, rather than heating it from the inside out or outside in. Since there is no temperature boundary, there is no chance for the water to re-freeze.