title: The effect of glass-forming sugars on vesicle morphology and water distribution during drying.
abstract: Cryopreservation requires that stored materials be kept at extremely low temperatures and uses cryoprotectants that are toxic to cells at high concentrations. Lyopreservation is a potential alternative where stored materials can remain at room temperatures. That storage process involves desiccating cells filled with special glass-forming sugars. However, current desiccation techniques fail to produce viable cells, and researchers suspect that incomplete vitrification of the cells is to blame. To explore this hypothesis, a cell is modelled as a lipid vesicle to monitor the water content and membrane deformation during desiccation. The vesicle is represented as a moving, bending-resistant, inextensible interface and is tracked by a level set method. The vesicle is placed in a fluid containing a spatially varying sugar concentration field. The glass-forming nature is modelled through a concentration-dependent diffusivity and viscosity. It is found that there are optimal regimes for the values of the osmotic flow parameter and of the concentration dependence of the diffusivity to limit water trapping in the vesicle. Furthermore, it is found that the concentration dependencies of the diffusivity and viscosity can have profound effects on membrane deformations, which may have significant implications for vesicle damage during the desiccation process.
authors.affiliation: Department of Engineering Sciences and Applied Mathematics, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3125, USA chris.j.vogl@gmail.com.
authors.forename: C J
authors.initials: CJ
authors.lastname: Vogl
authors.affiliation: Department of Engineering Sciences and Applied Mathematics, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3125, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Miksis
authors.affiliation: Department of Engineering Sciences and Applied Mathematics, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3125, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Davis
authors.affiliation: Department of Mechanical and Aerospace Engineering, The State University of New York at Buffalo, 318 Jarvis Hall, Buffalo, NY 14260-4400, USA.
authors.forename: D
authors.initials: D
authors.lastname: Salac
mesh_terms: D002241:Carbohydrates / Q000737:chemistry*; D022162:Cytoplasmic Vesicles / Q000737:chemistry / Q000648:ultrastructure*; D003890:Desiccation / Q000379:methods*; D008954:Models, Biological; D014021:Tissue Preservation / Q000379:methods*; D014783:Viscosity; D058989:Vitrification
chemical_list: D002241:Carbohydrates
keywords: concentration-dependent diffusivity; concentration-dependent viscosity; desiccation; lipid vesicle; lyopreservation; osmotic flow