TWith more than 4 hours remaining on ice， more than 60% of heart and lung donations are discarded each year. At present， vitrification （the biological sample super-frozen into a glassy state） is the only way to preserve tissue for a long time and can be used to preserve small biological samples such as sperm， eggs and umbilical cord blood. Although the method can be applied to make organ hypothermia preservation， in the thawing process， organ tissue will due to the formation of ice crystals be damaged or even broken.
　　Recently， the University of Minnesota research team developed a unique technology for rapid heating of frozen tissue. Professor John Bischoff of the Department of Biomedical Engineering and Mechanical Engineering at the University of Minnesota said that this technology does not compromise the activity of tissue cells， which undoubtedly overcomes a major obstacle in transplant medicine or preserves organ preservation.
　　The team mixes the magnetic nanoparticles into the cryogenic fluid and quickly and uniformly heats the entire sample by applying an external electromagnetic field. They tested the technique with frozen human skin cells， part of the pig heart tissue and large capacity （up to 50 ml） of the pig arteries， and the activity and functionality of the sample were fully restored. More importantly， after thawing， the nanoparticles can be completely eluted from the sample.
　　At present， animal organ related experiments have been in progress， it is possible in 7 to 10 years to start human organ preservation experiments.