Desiccation tolerance in human cells

The ability to desiccate mammalian cells while maintaining a high degree of viability would have implications for many areas of biological science, in cluding tissue engineering. Previously, we reported that introduction of th e genes for trehalose biosynthesis allowed human cells in culture to be rev ersibly desiccated for up to 5 days. Here, we have further investigated the factors that allow human cells to survive in the desiccated state. The mos t important finding is that vacuum greatly enhances the ability of human ce lls in culture to withstand desiccation. In fact, cells dried slowly and st ored under vacuum are able to withstand desiccation even in the absence of added carbohydrates or polyols. In addition to vacuum. the rate of desiccat ion, the temperature at which cells are maintained, the degree of confluenc e when dried, and the presence or absence of light have a large effect on t he ability to retain viability in the desiccated state, Our data are consis tent with a model in which cells can retain viability if they are desiccate d in such a way that cellular structures are maintained. However, gradual l oss of viability may be due to damage that occurs over time in the desiccat ed state, perhaps due to free radicals. Further optimization of the process for desiccating and maintaining cells is required before long-term storage of desiccated cells can be achieved. (C) 2001 Academic Press.