Temperature gradient osmometer and anomalies in freezing temperatures.
We have developed a new device that measures freezing and melting temperatures in nanoliter volume samples and can be used as a "freezing point osmometer" with a resolution many orders of magnitude greater than that of existing freezing point osmometers. Using this device we found anomalies in the depression of the freezing temperature and thermal hysteresis in aqueous solutions of hydrophilic amino acids, polyamino acids, and lectins. These anomalies would not have been possible to detect with currently used technology. The compounds that produce anomalies in freezing temperature were reported in the literature as having the ability to bind to cell membranes. This suggests a relation between a molecule's ability to bind to cell membranes and its anomalous freezing temperature depression. The new freezing point osmometer and our results could be important for studying and understanding organic molecules and their interaction with membranes and water.
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Department of Mechanical Engineering, University of California, Berkeley 94720.
Rubinsky
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D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D021301:Antifreeze Proteins; D004864:Equipment and Supplies; D005399:Fishes; D005615:Freezing; D006023:Glycoproteins / Q000737:chemistry; D037102:Lectins / Q000737:chemistry; D009994:Osmolar Concentration; D010455:Peptides / Q000737:chemistry; D037121:Plant Lectins; D011107:Polylysine / Q000737:chemistry; D012996:Solutions; D013816:Thermodynamics; D014867:Water
D000596:Amino Acids; D021301:Antifreeze Proteins; D006023:Glycoproteins; D037102:Lectins; D010455:Peptides; D037121:Plant Lectins; D012996:Solutions; C036554:dolichos biflorus agglutinin; D014867:Water; D011107:Polylysine; C011083:polyproline