The effect of glass-forming sugars on vesicle morphology and water distribution during drying
The effect of glass-forming sugars on vesicle morphology and water distribution during drying
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DOI：
10.1098/rsif.2014.0646
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发表时间：
2014-10
影响因子：
3.9
通讯作者：
C. Vogl;M. Miksis;S. H. Davis;D. Salac
中科院分区：
文献类型：
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作者：
C. Vogl;M. Miksis;S. H. Davis;D. Salac
冷冻保存要求储存的材料保持在极低的温度下，并使用高浓度时对细胞有毒的冷冻保护剂。冷冻保存是一种潜在的替代方法，其中储存的材料可以保持在室温下。该储存过程涉及干燥充满特殊玻璃糖的细胞。然而，目前的干燥技术无法产生活细胞，研究人员怀疑细胞不完全玻璃化是罪魁祸首。为了探索这一假设，将细胞建模为脂质囊泡，以监测干燥过程中的水含量和膜变形。囊泡被表示为一个移动的、抗弯曲的、不可延伸的界面，并通过水平集方法进行跟踪。将囊泡置于含有空间变化的糖浓度场的流体中。玻璃形成性质通过浓度相关的扩散率和粘度进行建模。研究发现，渗透流参数值和扩散率的浓度依赖性存在最佳状态，以限制囊泡中的水截留。此外，发现扩散率和粘度的浓度依赖性会对膜变形产生深远的影响，这可能对干燥过程中囊泡的损伤产生重大影响。
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.