Abstract
For a better understanding of the mechanism of ice formation in biological systems, more basic studies concerning physical properties of water at low temperatures and ice formation in aqueous solutions are required. In the case of ice nucleation in aqueous solutions, for example, structural compatibility/incompatibility between water, ice and solute molecules is essential. The fact may lead to the recognition that even isotropic aqueous solutions are not homogeneous microscopically. Biological systems are macroscopically heterogeneous and aqueous solutions in them are sometimes confined in small spaces or compartmentalized by the cross-linked network structures. In this case, size and structure of the space where aqueous solutions freeze should be taken into consideration.
Therefore, basic studies of freezing of heterogeneous systems are encouraged for a better understanding of the mechanism of ice formation in biological systems, which might be necessary for the development of the technique of their cryo-preservation.
