Method of freezing human blood platelets in glycerol-glucose using a statically controlled cooling rate device

A method for cryopreserving cellular suspensions, such as red blood cells, granulocytes and platelets, comprising:

• placing a plastic freezing bag containing the cellular suspension admixed with a liquid cryoprotective agent between a pair of thermally insulating plates, placing said thermally insulating plates with said freezing bag between a pair of hinged metal plates, the plastic freezing bag containing said cellular suspension being placed between said pair of metal plates so that said pair of metal plates include a small or minor angle therebetween, the pair of metal plates assuming a wedge shape when viewed from the side, affixing together, such as by taping, the pair of metal plates so as to secure the plastic freezing bag containing said cellular suspension therebetween, placing the assembly with a larger outer plastic freezing bag, submerging the resulting assembly in a substantially vertical position within a pool of liquid nitrogen such that the upper surface of the pool of liquid nitrogen is above the top of the plastic freezing bag containing said cellular suspension but below the top of the outer freezing bag such that the liquid nitrogen does not come into direct contact with the plastic freezing bag containing the cellular suspension to be frozen, permitting the resulting assembly to be thus submerged within said liquid nitrogen for a period of time to freeze said cellular suspension and thereupon transferring the resulting assembly, now containing frozen cellular suspension, to the space above the liquid level of said liquid nitrogen for cryostorage.