vitrification and anhydrobiosis

Doug Skrecky (
Thu, 3 Sep 1998 13:45:50 -0700 (PDT)

Crowe JH. Carpenter JF. Crowe LM.
Section of Molecular and Cellular Biology, University of California, Davis 95616, USA.
The role of vitrification in anhydrobiosis. [Review] [86 refs]

Annual Review of Physiology. 60:73-103, 1998. Abstract
Numerous organisms are capable of surviving more or less complete dehydration. A common feature in their biochemistry is that they accumulate large amounts of disaccharides, the most common of which are sucrose and trehalose. Over the past 20 years, we have provided evidence that these sugars stabilize membranes and proteins in the dry state, most likely by hydrogen bonding to polar residues in the dry macromolecular assemblages. This direct interaction results in maintenance of dry proteins and membranes in a physical state similar to that seen in the presence of excess water. An alternative viewpoint has been proposed, based on the fact that both sucrose and trehalose form glasses in the dry state. It has been suggested that glass formation (vitrification) is in itself sufficient to stabilize dry biomaterials. In this review we present evidence that, although vitrification is indeed required, it is not in itself sufficient. Instead, both direct interaction and vitrification are required. Special properties have often been claimed for trehalose in this regard. In fact, trehalose has been shown by many workers to be remarkably (and sometimes uniquely) effective in stabilizing dry or frozen biomolecules, cells, and tissues. Others have not observed any such special properties. We review evidence here showing that trehalose has a remarkably high glass-transition temperature (Tg). It is not anomalous in this regard because it lies at the end of a continuum of sugars with increasing Tg. However, it is unusual in that addition of small amounts of water does not depress Tg, as in other sugars. Instead, a dihydrate crystal of trehalose forms, thereby shielding the remaining glassy trehalose from effects of the added water. Thus under less than ideal conditions such as high humidity and temperature, trehalose does indeed have special properties, which may explain the stability and longevity of anhydrobiotes that contain it. Further, it makes this sugar useful in stabilization of biomolecules of use in human welfare. [References: 86]

Additional note by poster:

Practical application of anhydrobiosis on human organ systems at present can not use sugars because of their very poor penetration ability. Animals which can enter anhydrobiosis have special sugar transporters for example on their cell membranes.
However some sugar alcohols like erythritol readily penetrate human tissue, are completely non-toxic (not metabolized), and offer the potential for good freeze-dry preservation of tissue, albet at storage temperatures somewhat below ambient.