Tissues and cells can be preserved at sub-zero temperatures by adding a cryoprotectant such as propanediol or dimethyl sulphoxide, but these can be toxic at the concentrations needed to prevent damaging ice crystals from forming. Rapid heating allows a lower concentration of cryoprotectant to be used, and to achieve this we place the sample at the centre of a purpose-built resonant cavity and apply high power radio waves at 430MHz. We monitor the temperature with a fibre-optic thermometer. This work is in collaboration with the David Pegg and colleagues at the Medical Cryobiology Unit and has been funded by BBSRC.