Transport Characteristics of Glycerol and Propylene Glycol in an Engineered Dermal Replacement

Abstract

The ability to cryopreserve engineered tissues is important for the clinical application of therapies based on living cells. Cryopreservation facilitates the manufacture, transport and safety of cell-based therapies. The cryopreservation of cells and tissues had typically required the use of specialized solutions containing cryoprotective agents (CPAs). The addition of a CPA to the freezing solution may result in damage if it is not done properly. Tissues and intact organs can exhibit reduced cellular viability when exposed to sufficiently large step changes in external osmolarity resulting from introduction or removal of a cryopreservation solution (Pegg, 1972). Not only are large step changes in osmolarity potentially damaging, but also long-term exposure to even low concentrations of CPAs at room temperature can be lethal (Fahy et al., 1990). Exposure of cells to CPAs (in particular dimethyl sulfoxide, Me2SO) has been associated with a loss in viability with time of exposure. Subsequent studies have quantified specific cellular changes resulting from exposure to CPA, such as cytoskeletal reorganization, cross-linking of nuclear proteins, and alterations in membrane permeability (cf. ref (Fahy et al., 1990) for review) which may account for the loss in viability.