Damage of cells by cryopreservation

Reproducible and reliable cryopreservation of blood cells by freeze-drying is a difficult goal to achieve. During the freeze-drying process of cells, their cell membrane or macromolecular contents are susceptible to damage. In this paper, the general process of freeze-drying as a means to achieve cryopreservation is described.In order to guarantee reproducible and reliable cryopreservation by freeze-drying, it is essential to: (a) recognise the physicochemical and technical parameters which affect the quality/activity of freeze-dried blood cells and constituents and (b) have knowledge of the quantitative interrelationships between these parameters.To ensure an optimal process it is necessary for instrumentation to be supplemented with computer control and vacuum lock sampling. In the preservation of structural and functional integrity of cells, residual water left after freeze-drying is crucial. Using curves relating activity to residual moisture content, an optimum can often be found.