Cryogenic is the science of producing and using very low temperature. The study of low temperature effects in biology and medicine is called cryobiology. Low temperature can be produced by liquefying gases. It was succeeded to produce liquid air (-196 oC ) and liquid helium ( -269o C ). For solid CO2 it is ( -79 oC ) and liquid nitrogen (-196 °C ) .
These cold liquids have many medical and biological advantages. There are many problems with these gases and liquids like storage and transfer because they absorb heat by conduction, convection and radiation. So they have to be kept in a special container and transferred by special pipes.