TEMPERATURE-GRADIENT OSMOMETER AND ANOMALIES IN FREEZING TEMPERATURES

We have developed a new device that measures freezing and melting temp eratures in nanoliter volume samples and can be used as a ''freezing p oint osmometer'' with a resolution many orders of magnitude greater th an that of existing freezing point osmometers. Using this device we fo und anomalies in the depression of the freezing temperature and therma l hysteresis in aqueous solutions of hydrophilic amino acids, polyamin o acids, and lectins. These anomalies would not have been possible to detect with currently used technology. The compounds that produce anom alies in freezing temperature were reported in the literature as havin g the ability to bind to cell membranes. This suggests a relation betw een a molecule's ability to bind to cell membranes and its anomalous f reezing temperature depression. The new freezing point osmometer and o ut results could be important for studying and understanding organic m olecules and their interaction with membranes and water.