Cryopreservation is the process of freezing organs and tissues at very low temperatures in order to preserve them. While it sounds simple in theory, only a handful of cells and tissues have survived this method. This is because while science has successfully developed ways to cool organs to the very low temperatures required for preservation, thawing them out has proven far more difficult. As the specimen thaws, it forms ice crystals, which can damage the tissue and render organs unusable.

Right now, the process is only a viable option for small samples, such as sperm or embryos. Previous efforts using slow warming techniques have proven to be effective on samples of that size, but haven’t worked for larger tissue samples, like whole human organs. The inability to safely thaw the tissue has also precluded the theoretical concept of cryogenically preserving entire human bodies, with the intention of reanimating them later. The concept has roots in cryogenic technology, but is actually referred to as “cryonics”, and the scientific community generally considers it to be more science fiction than science fact — at least for the time being.

A recent study has made a significant breakthrough which may well begin closing that gap even more. Using a new technique, scientists were able to cryopreserve human and pig samples, then successfully rewarm it without causing any damage to the tissue.