Survival of Desiccated Mammalian Cells: Beneficial Effects of Isotonic Media

Abstract

Efforts to improve the tolerance of mammalian cells to desiccation have focused on the role that sugars have in protecting cells from lethal injury. The objective of this study was to examine the effect that the composition of intra- and extracellular trehalose solutions has on the survival of dried 3T3 fibroblasts. Trehalose was introduced into 3T3 fibroblasts using a genetically engineered mutant of the pore-forming α-hemolysin from Staphylococcus aureus. Cells were dried using natural convection at ambient temperatures. Plasma membrane integrity and the ability to grow and divide in culture were used to assess cell survival. We found that the post-rehydration membrane integrity and percent cell growth were a function of the residual moisture content of the cells following drying. Adjusting the initial osmolality of the intra- and extracellular sugar solutions to isotonic levels by reducing the concentration of buffer resulted in a significant improvement in the membrane integrity and growth of dried cells. 3T3 fibroblasts dried to 10% residual moisture content in an isotonic solution of 0.2 M intra- and extracellular trehalose exhibited greater than 90% membrane integrity and approximately 70% growth. Understanding the biological response to desiccation will be critical in developing effective strategies for the drying of mammalian cells.