Antifreeze Proteins Can Stop Ice Melt

First Direct Measurements of “Superheating” Phenomenon

Mar. 10, 2010

A crystal of ice protected by anti-freeze proteins, can withstand cooling (left) and melting (right). In contrast, ice that grows quickly in a snowflake formation in cold temperatures (middle), is not protected and melts quickly in warm temperatures (right). Credit: > Reproduced from Celik et al. PNAS. Early Edition 9 March 2010

A crystal of ice protected by anti-freeze proteins, can withstand cooling (left) and melting ... more

The same antifreeze proteins that keep organisms from freezing in cold environments also can prevent ice from melting at warmer temperatures, according to a new Ohio University and Queen's University study published in the Early Edition of the journal Proceedings of the National Academy of Sciences. Antifreeze proteins are found in insects, fish, bacteria and other organisms that need to survive in cold temperatures. These proteins protect the organisms by arresting the growth of ice crystals in their bodies. The new study not only has implications for understanding this process in nature, but also for understanding the superheating of crystals in technologies that use superconductor materials and nanoparticles.
The researchers provide the first experimental evidence that superheated ice crystals can be stabilized above the melting point for hours, at a maximum temperature of about +0.5 °Celsius. Superheated crystals rarely stay stable for long periods of time, and previous studies showed that stabilization only occurs under unique conditions, Ido Braslavsky, an associate professor of physics and astronomy at Ohio University, explained. The researchers used two techniques in the study, fluorescence microscopy and sensitive temperature control of a solution within a thin cell. In order to track the position of the antifreeze protein on an ice crystal, the researchers attached a second protein to the antifreeze protein-the green fluorescent protein, which glows under certain conditions. The scientists then placed the antifreeze protein solution in the thin cell, which allowed them to observe the fluorescence signal from the protein while finely controlling the ice crystal's temperature. These findings potentially could make the process of ice recrystallization inhibition more efficient for applications such as maintaining the quality of frozen foods, Braslavsky said.

Original publication:
Celik Y., et al.: Superheating of ice crystals in antifreeze protein solutions. PNAS March 9, 2010 published online before print, doi: 10.1073/pnas.0909456107

Imaging-GIT.com

News

Antifreeze Proteins Can Stop Ice Melt

First Direct Measurements of “Superheating” Phenomenon

Reader comments (0)

GIT Verlag