Does cryopreservation work? If not, then will it eventually work in the future so that you can freeze your body, and

Question: Does cryopreservation work? If not, then will it eventually work in the future so that you can freeze your body, and then wake up many years in the future - In the same state as before you were frozen - with no health issues or negative affects to your body, and with all your memories etc.?
- Keywords:
  body,
  cryogenics,
  future
Asked by anon-220785 on 19 Jun 2019.
- Matthew Bareford answered on 19 Jun 2019:
  
  Currently We can freeze someone’s body using something like liquid nitrogen and it will be frozen and ‘preserved’ but we have no way to safely thaw them out….
  
  Freezing a cell would mean that it would freeze all of the water in it. Freezing the water would mean it would expand and then the cell membranes would burst and die….
  
  There are some animals: that can do this, such as the Wood Frog.
  
  you can find out some more of this information here:
  
  These 6 Animals Can Freeze—And Then Come Back To Life!
- David Wilson answered on 19 Jun 2019:
  
  We can freeze cells that we grow in the lab and bring them back to life again.
  One of the first challenges we face in freezing tissue is how to do it without damaging the cells. If you freeze something slowly then water in the cells forms ice crystals, this is why ice cream that has been thawed and frozen again can be “crunchy”. In tissue these ice crystals cause the cells to burst so that they don’t work when thawed. So we can either “snap freeze” tissue really fast using Liquid Nitrogen (−195.79 °C) or we can use a cryoprotectant like DMSO which stops ice crystals having such sharp pointy edges and can freeze cells it a bit more easily at −80 °C.
- Marianne King answered on 19 Jun 2019:
  
  We can cryopreserve cells by freezing them in liquid nitrogen or really cold freezers (-120oC) but the only reason they survive is because we add something called DMSO to them, as David said. This helps the cell membranes become softer so they’re not as upset by ice crystals, and the DMSO itself also helps stop ice crystals forming. Making a human drink DMSO would probably make them quite unwell so I’m not sure how we’d be able to safely freeze a human or defrost them again!
  
  I’ve just found something called the Cryonics Institute where people do freeze their whole body in the hope that they can one day be resuscitated into a utopian world! The minimum fee is $28,000 to do this which they say is cheap… but I respectfully disagree. They claim that they halt the process of death and then they can revive you at a time when science would be able to save you. I guess we’ll have to wait and see on that one as I don’t think it’s ever been done before!
- Kaitlin Wade answered on 19 Jun 2019:
  
  Like others have said here, the problem isn’t necessarily that freezing doesn’t work but we just don’t know at the moment a safe way to thaw the cells in a way that wouldn’t be damaging for the cells. It’s an awesome thought though! I think about this sometimes and think it would be interesting to thaw way in the future to see what the world has become!
- Nina Rzechorzek answered on 20 Jun 2019:
  
  It is possible to bring a very cold human ‘back to life’ after their heart has stopped beating – I think the lowest body temperature ever recorded in someone that made a full recovery from accidental extreme hypothermia was 13.7 degrees celsius (but many people have died from hypothermia at temperatures much higher than this). The resuscitation process involved very slow rewarming and took over 9 hours. ‘Therapeutic hypothermia’ to between 32 and 35 degrees celsius is used to protect the brain from injury in babies that have been starved of oxygen at birth, and for some heart surgeries. As far as I am aware, although several humans have been ‘cryopreserved’, no human has yet been recovered or thawed out because we don’t know how to do this safely. I do believe we will one day have the resources and knowledge to do this – most likely learning from nature itself. The brains of Arctic ground squirrels reach near-freezing temperatures during bouts of hibernation and when these animals come out of hibernation their brains still work fine. Key to this resilience is possibly that they interrupt their hibernation with frequent periods of arousal – potentially to recover some of the brain connections that were lost during cooling. Some of these mechanisms are helping us to understand brain plasticity and even dementia! There is a nice summary of this topic here:
  https://www.scientificamerican.com/article/arctic-ground-squirrel-brain/
- Kate Timms answered on 20 Jun 2019:
  
  As others have said, it’s probably not the freezing that’s the problem, but the thawing again. When you freeze cells (or even whole tissues or animals) then ice crystals form inside the cytoplasm inside the cell. To give cells the best chance of surviving we freeze them slow as possible, often using special ‘pods’ designed to reduce their temperature slowly. The faster you freeze, big, sharp ice crystals can form. So freezing slowly with a cryopreservent (a chemical which helps cells survive freezing) that allows water to escape cells and reduce ice crystal formation is best for keeping cells alive.
  
  We then have to defrost really quickly to make sure the ice crystals that do form can melt really quick, doing minimal damage to the cells. If you think about it, the bigger something is, then longer it takes to defrost. So defrosting a whole body would be really slow and would cause massive amounts of damage to our cells, including the neurons in our brains. And making it really hot so that a body would defrost quickly would also be bad because it could essentially cook our extremities whilst our middles would still be frozen! Not a good situation to be in!