The present invention relates to a gas delivery device comprising a gas releasing molecule and a gas permeable membrane. The invention also relates to the use of the gas delivery device for delivery of gas to an extracorporeal transplant, extracorporeal cells, a brain-dead transplant donor or foodstuff and in therapy. The invention further relates to the use of a gas permeable and liquid and solid impermeable membrane to separate a gas releasing molecule and its non-gaseous degradation products from an extracorporeal transplant, extracorporeal cells, a brain-dead transplant donor or foodstuff.