Untersuchungen zur Gefriertrocknung biologischer Zellen am Beispiel menschlicher Erythrozyten
Freeze-drying is a state of the art process for stabilization of pharmaceutical or biotechnological products. However, a successful preservation of living cells by freeze-drying is still a big challenge. This is mainly due to increased requirements on the product quality, since even smallest structural changes of the complex cell morphology can lead to a loss of function or viability. Using human erythrocytes as a simple model for biological cells in general, several mechanisms were investigated presumed to be responsible for cell damage during the freeze-drying process. Besides a considerable progress in understanding of these mechanisms, the cell recovery rate could gradually be increased from about 0% to 50% by means of following major developments and studies. A new low-temperature freeze-drying device was designed and manufactured that allows a controlled cooling of condenser and shelf down to >190°C and >80°C, respectively. A variation of shelf temperature and drying time led to optimized vacuum-drying conditions. The temperature inside the sample, which was either measured or calculated, was found to be a key quantity for the resulting cell damage. A cooling rate variation showed that ultra rapid cooling with a rate of up to 13.500 K/min leads to amorphous sample structures providing best cell protection during subsequent drying.
info:eu-repo/classification/ddc/660, Technische Chemie, Erythrozyt, Gefriertrocknung, Prozessoptimierung, Gefrieranlage, Technikumsanlage
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