PITTSBURGH-Carnegie Mellon University's Yoed Rabin has received three grants totaling $1.26 million from the National Institutes of Health (NIH) to develop biothermal technology for low temperature applications ranging from cryopreservation to cryosurgery. Cryopreservation is the preservation of tissues and organs at very low temperatures with potential benefit to transplantation and regenerative medicine, whereas cryosurgery is the controlled destruction of undesired tissues by freezing, such as cancerous tumors.

"Ice crystallization is the cornerstone of tissue injury at low temperatures, where the outcome of cryogenic exposure is essentially related to the ability to control the formation of ice,''said Rabin, a mechanical engineering professor at Carnegie Mellon.

A promising method for cryopreservation is known as vitrification (glassy), where ice formation is prevented, and the tissue transforms into a complex glassy material.

"Unfortunately, common materials to promote glass formation are very toxic to the tissue, and the development of less harmful materials represents a major effort at the forefront of cryopreservation research,'' said Rabin.

With support of one NIH grant, Rabin is investigating the effects of combining exotic compounds known as synthetic ice blockers with common glass-promoting materials, in an effort to achieve vitrification in more favorable conditions to the tissue.

Through support of a second NIH grant. Rabin is developing a device to visualize the effects associated with cryopreservation, such as glass formation, crystallization and structural changes.

"Contrary to cryopreservation, ice formation is the key to cryosurgery success,'' said Rabin.

And with support of a third NIH grant, Rabin is leading a team effort to develop wireless, implantable temperature sensors, to assist in temperature monitoring and control of the cryosurgical procedure. The sensors would be strategically placed through a hypodermic needle prior to the operation, and communicate with a wireless server during the operation, in an effort to generate the developing 3D temperature field in the tissue in real time.

"While the wireless temperature sensor is being developed for cryosurgery, it can also be used to monitor and control cryopreservation protocols, which signifies the potential impact of the developed technology,'' said Rabin.