Associate Professor (Physics and Astronomy)

Currently on leave from Ohio University
Performing research at The Hebrew University of Jerusalem

O: Clippinger 155
T: 740-597-3011
F: 740-593-0433
E: braslavs@ohio.edu

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The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment

Many organisms are protected from freezing by antifreeze proteins (AFPs), which bind to ice, modify its morphology, and prevent its further growth. Since the initial discovery of AFPs in fish, they have been found in insects, plants, bacteria and fungi. These proteins have a wide range of applications in cryomedicine, cryopreservation and frost protection for transgenic plants and vegetables. AFPs also serve as a model for understanding biomineralization, the processes by which proteins help form bones, teeth and shells. Yet the mechanism of action of different types of antifreeze proteins is incompletely understood.

In Braslavsky’s group, the kinetics of the interaction between AFP and ice is monitored by fluorescence microscopy. Several types of AFPs labeled with a fluorescent marker have been prepared mainly by our collaborator Peter Davies. By putting a fluorescent tag on a fish AFP, we were able to directly visualize AFP binding to ice and demonstrate, by lack of recovery after photo-bleaching, that a fish AFP from ocean pout (type III) adheres irreversibly to ice surfaces. Additionally, we observed fluorescently labeled hyperactive insect antifreeze protein from spruce budworm on ice crystals. We find that differences between antifreeze protein types are manifested not only by the shape of the ice crystals but also in the way proteins interact with the ice.

We are currently developing devices that can monitor the fluorescently labeled proteins with high sensitivity. Braslavsky’s group developed microfluidic devices in which the composition of the solution around tiny ice crystals can be changes. We plan to use these devices soon to further explore the behaviors of the antifreeze proteins and their interaction with ice. The system of AFPs and ice can be used as a model platform to understand bio-mineralization processes and thus its importance for future nanotechnology applications. This project is sponsored by NSF. Currently the research is conducted at the Hebrew University of Jerusalem at Rehovot, Israel. Research position at the level of Master or PhD are available. The research will be conducted in Israel, while course studies will be at Ohio University.