Thermoreversible gelation of atactic polystyrene solutions

Biophysical chemical aspects of cellular cryobehavior

Freezing tolerance and resistance in nature are among the most important and challenging aspects of biochemical adaptation to extreme environments. Some biochemical strategies are known but their mechanism is still poorly understood. Cryopreservation of cells and tissues of sensitive organisms is still generally based on physical chemistry rather than on biophysical chemical mechanisms. This paper describes the main aspects of these problems and features new trends in their study.

Thermal behavior of collagen and agarose solutions and its possible implications in the cryobehavior of living systems

Commonly used cryopreservation procedures are empirical and involve incompletely understood phenomena. Our purpose is to study in vitro the cryobehavior of a number of biopolymers participating in cell structure or its environment. Their abilities to interact with water to obtain gelified structures might be a good means to reduce the water mobility, and thereby decrease the often lethal consequences of the latter's crystallization. Our preliminary results concerning collagen and agarose, representative constituents of the extracellular matrix, indicate that cooling/warming rates and the presence of organic solvents may alter the thermal behavior and structure of these biopolymers, and suggest that such types of responses may influence the cryobehavior of cells and extracellular matrices.