| Cryobiology is a multidisciplinary science to study the physical and biological behaviors of cells and tissues at low temperatures. It is a thriving and prosperous area with an associated, increased need for the development of improved, efficient preservation methods and technologies for living cells to provide "cell banks". Several novel technologies including the novel box-in-box system, the diffusion system for cryoprotective agents (CPAs) removal system, and the lyophilization of human Erythrocyte have been studied in this thesis.; For cryopreservation of hematopoietic stem cells (HSCs), cooling rate is a dominant factor influencing the survival of the cells. It is one of the objectives of this thesis to develop a novel cooling system (box-in-box system) to achieve the optimal cooling rates (1∼3°C/min) for cryopreservation of cord blood units. The system can be used to cryopreserve the stem cells cheaply, reliably and safely. Numerical simulation is conducted to analyze the influence of several factors on the performance of the cooling system, and to design the system for the cryopreservation of other types of cells or even tissues.; A major difficulty associated with using cryopreserved HSCs clinically is the current complexity associated with DMSO removal, which will introduce mechanical forces and osmotic stress causing cell packing/clumping and potential significant cell loss. It is also an objective of this thesis to develop a closed diffusion washing system for removal of CPA (DMSO) from thawed cord blood units. Numerical simulation was also carried out with a modified "equivalent annulus" model to calculate the combined diffusion-convection mass transfer rigorously. The program can be used to simulate the concentration change of CPA as the cell suspension flow through the mini-module.; It is another goal of this thesis to experimentally study, the leading technology---the freeze-drying of human red blood cells. The effect of several factors on the recovery rate of red blood cells after freeze-drying and rehydration has been studied. These factors include types, concentration of the additives such as carbohydrate and polymers, and the method of rehydration. We also found that the concentration of glucose is critical to the RBCs viability recovery, too high or too low concentration will make it worse than the optimal concentration: 22.5%. The final experimental results are encouraging, the recovery of intact cells, hemotocrits, and hemoglobin of 85.0 +/- 8.90, 87.56 +/- 8.02%, and 68.39 +/- 6.72%, respectively with a lyophilization buffer composed of 22.5% glucose, 15% PVP and 5% BSA. |
