Differential scanning calorimetry applied to the preservation of bacteria and mammalian cells
Résumé
Cell preservation processes involve variations in cell concentrates temperature during production, stabilization, transport and storage. Freezing and freeze-drying are the most commonly used stabilization processes. The temperature changes they induce cause modifications in the state of water and alterations in the physical and chemical properties of the cells and the extracellular medium. The matrix surrounding the cells generally contains protective molecules to limit the damage suffered by the cells during the freezing and freeze-drying processes. Differential scanning calorimetry (DSC) is a powerful tool for better understanding the influence of temperature on the properties of cell concentrates. It is also helpful for optimizing the matrix's composition and preservation conditions in terms of product quality and process efficiency. This presentation focused on the relevance of physical properties such as the glass transition temperature determined by DSC for improving the survival to freezing and freeze-drying bacteria and mammalian cells. Through several examples involving different cell types and protective matrix, the main achievements and limits of this technique were discussed.