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In JoVE (1)
Other Publications (1)
Articles by Ran Drori in JoVE
JoVE Chemistry
LabVIEW-operated Novel Nanoliter Osmometer for Ice Binding Protein Investigations
1Institute of Biochemistry, Food Science, and Nutrition , The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, 2Department of Physics and Astronomy, Ohio University
Ice binding proteins (IBPs), also known as antifreeze proteins, inhibit ice growth and are a promising additive for use in the cryopreservation of tissues. The main tool used to investigate IBPs is the nanoliter osmometer. We developed a home-designed cooling stage mounted on an optical microscope and controlled using a custom-built LabVIEW routine. The nanoliter osmometer described here manipulated the sample temperature in an ultra-sensitive manner.
Other articles by Ran Drori on PubMed
Microfluidic Experiments Reveal That Antifreeze Proteins Bound to Ice Crystals Suffice to Prevent Their Growth
Antifreeze proteins (AFPs) are a subset of ice-binding proteins that control ice crystal growth. They have potential for the cryopreservation of cells, tissues, and organs, as well as for production and storage of food and protection of crops from frost. However, the detailed mechanism of action of AFPs is still unclear. Specifically, there is controversy regarding reversibility of binding of AFPs to crystal surfaces. The experimentally observed dependence of activity of AFPs on their concentration in solution appears to indicate that the binding is reversible. Here, by a series of experiments in temperature-controlled microfluidic devices, where the medium surrounding ice crystals can be exchanged, we show that the binding of hyperactive Tenebrio molitor AFP to ice crystals is practically irreversible and that surface-bound AFPs are sufficient to inhibit ice crystal growth even in solutions depleted of AFPs. These findings rule out theories of AFP activity relying on the presence of unbound protein molecules.
