The cryoprotective action of synthetic glycolipids

Egg PC vesicles frozen and thawed in the presence of carbohydrate derivatives do not incur damage normally associated with freeze thawing. Treated vesicles maintain membrane integrity as evidenced by the lack of lipid intermixing and maintenance of vesicle size following freezing and thawing. This protection is conferred at a derivative:lipid ratio of 0.4 mol/mol, significantly lower than the amount of carbohydrate required when not attached directly to the vesicle. This result indicates that only the carbohydrate at the vesicle surface is responsible for imparting stability to the membrane. This effect can be modulated by variations in the nature of the surrounding medium or alterations in the structure of the carbohydrate, suggesting that direct interactions between the carbohydrate and membrane occur at the membrane interface which are sensitive to bulk phase properties.