Hypothermic preservation of biological tissues and cells

A method for hypothermic preservation of biological tissue for later recovery to a viable state includes flushing the biological tissue with a gas mixture of sulfur hexafluoride or xenon and oxygen. The sulfur hexafluoride or xenon is in a concentration in the mixture between about 75 mole percent to 95 mole percent. The method includes pressurizing the biological tissue, preferably isothermically, with the mixture to a pressure that will form clathrates inside the biological tissue at a desired storage temperature in a range of about +1° C. to about +5° C. The method includes a step of cooling the biological tissue, preferably isobarically, to the desired storage temperature. Optional steps for further cooling to no colder than about −20° C. and for depressurization are provided as well as steps for recovering the hypothermically preserved biological tissue to a viable state, preferably using a recovery gas mixture.