From Water to Ice: Investigation of the Effect of Ice Crystal Reduction on the Stability of Frozen Large Unilamellar Vesicles

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The solid phase of water, ice, is generally detrimental to cells because it causes freeze injury of cells during cryopreservation. Nonpermeable cryoprotective agents (CPAs) such as sucrose, trehalose, and glucose and/or permeable CPAs such as dimethyl sulfoxide (DMSO) and ethylene glycol (EG) are often added to freezing solutions to reduce such effects. The effect of ice formation on the stability of phospholipid bilayers was investigated using a model membrane: 1,2 - dipalmitoyl - rac - glycero - 3 -phosphocholine (DPPC) large unilamellar vesicles (LUVs) encapsulated with carboxyfl uorescein (CF) solution. The LUV dispersion was added with a CPA, cooled to 40 ° C, and heated to 20 ° C at 10 ° C/min. LUV stability was described by the degree of CF leakage. In the presence of sugars, DMSO, or EG, ice formation was reduced. Simultaneous to the ice reduction, an increase of unfrozen fraction prevented LUV aggregation and leakage. The leakage was observed to decrease above a defi ned sugar concentration and as the concentration of DMSO or EG increased. Below the defi ned sugar concentration, LUV leakage increased with increasing sugar concentrations. Nonpermeable CPAs were more effective for the frozen LUVs compared to permeable CPAs. The current result suggests that LUVs were spaced out from one another in the presence of nonpermeable CPAs. On the other hand, LUVs in 10% (wt/wt) of permeable CPAs could probably undergo structural destabilization.

Original languageEnglish
Title of host publicationWater Properties in Food, Health, Pharmaceutical and Biological Systems : ISOPOW 10
Number of pages12
Publication date14 May 2010
ISBN (Print)9780813812731
Publication statusPublished - 14 May 2010

    Research areas

  • Cryopreservation - usage in biopreservation, preserving organisms at low temperature, Cryoprotective agents (CPAs) addition - improving cell survival during cryopreservation, Effect of ice crystal reduction - stability of frozen large unilamellar vesicles, Ice - detrimental to cells, freezing injury of cells during cryopreservation, Increase of unfrozen fraction - preventing LUV aggregation and leakage, Permeable CPAs - suppressing intracellular ice formation, Successful cryopreservation - survival of the frozen organisms after warming ice

ID: 299416536