Interaction of water with native collagen

Abstract

Abstract The interaction of water with collagenous tissue was investigated using dynamic mechanical spectroscopy and cryogenic X‐ray techniques. The loss spectrum was found to be very sensitive to water which is highly associated with the macromolecule. Two water‐sensitive loss peaks were observed below 0°C: the β 2 or “water dispersion” at 150°K and the β 1 at 200°K which is attributed to motion of polar side chains. Changes in peak temperature and intensity were not continuous with water content, but exhibited regimes in behavior which were associated with two types of nonfreezable water, structural and bound water. In cryogenic X‐ray experiments, specimens which contained some freezable water exhibited reflections identified with the cubic form of ice. These ice crystals underwent an irreversible transition to the more common hexagonal form when warmed above 200°K. On the basis of these experiments, a model for the hydration of native collagenous tissue was proposed.