Snap Freezer for ISS

Frozen tissue samples represent the state of the art in tissue preservation in many molecular analysis techniques as well as in in membrane analysis using free-fracture techniques. Rapid or snap freezing eliminates the artifact caused by ice crystal formation within the tissues. Ice crystal nucleation and growth occurs between 0 degrees C and -20 degrees C typically. To avoid this damage and minimize destruction of proteins, RNA and DNA by lytic enzymes, cells or tissues have to be rapidly cooled through this temperature band. This is typically done in an isopentane bath cooled by liquid nitrogen (LN2) to -150 degrees C. This 2 step process eliminates artifacts caused by ice nucleation as well as artifacts caused by nitrogen bubbles that surround the tissue as it boils if submerged directly into LN2. While these open methods are acceptable for terrestrial laboratories, they would not be compatible with experimentation on the International Space Station. Our proposed argon based Snap Freezer clamp would provide an alternative means to rapid cool through ice crystal nucleation and growth temperatures without exposing the crew to the spill hazards of LN2 and chilled isopentane as well as the extreme flammability of isopentane.