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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.
There are a few ways of freezing samples without creating ice crystals. Part of the trick is to freeze it *fast*. But water is still a problem, becuase even with super rapid freezing, overtime the crystals will restructure into sharp ice. Bad. Nitrogen would seem the obvious, but it tends to boil at the contact point leaving pockets of gaseous nitrogen to slow down the penetration of cold leaving the centres of samples to slowly ice and form crystals. Isopentane doesnt have the low boiling point issue so it works a lot better Glycerine is often used in storing cell cultures. And so on.
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."
I know it was demonstrated awhile back that a rabbit kidney could be cryopreserved and then restored to function.
Seriously, the longer I live, the more it seems plausible that one day it will be possible to cryopreserve a human brain and restore it to function later. One day human lifespan may be greatly extended in a way that looks like this:
McCoy: "He's dead, Jim."
Kirk: "Bones, do something!"
McCoy: "Sorry, Jim, there isn't anything I can do."
KirK: "Why?"
McCoy: "Because he's dead."
Kirk: "How do you know he's dead?"
McCoy: "Because there's nothing I can do."
Kirk: "Because he's dead?"
McCoy: "That's right."
Kirk: "But I was talking to him just one minute ago!"
McCoy: "Dammit Jim, I'm a doctor not a spiritual medium! I can't bring back the dead anymore than I can cure a common cold."
Spock: "Doctor, we could take him back to the ship, dissolve any blood clots, restore circulation, and restore homeostasis by molecular repair. He could fully resume duty within days."
McCoy: "Spock, leave doctoring to doctors! What this man needs is a decent burial."
Secession is the right of all sentient beings.
The photos are legit. 50 ml is a sizeable thaw sample. My biochem circuits assesses this as a considerable advance for cryogenics. YES The trials stop at 50 ml, which these days means larger volumes failed. NO It does not allow a human brain mass to be thawed. But, smaller thaws are still great news. Basic research would see a tremendous boon if experiments can be performed with larger frozen sample sizes. A great number of potential medical treatments would become feasible with a 50x advance in cryogenic thawing. Some people here need an opinion reboot. This is exciting news!
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 ]
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.