TY - JOUR
T1 - Cryo-responses of two types of large unilamellar vesicles in the presence of non-permeable or permeable cryoprotecting agents
AU - Siow, Lee Fong
AU - Rades, Thomas
AU - Lim, Miang Hoong
N1 - Funding Information:
This work is supported by the Department of Food Science, University of Otago.
Funding Information:
We thank Liz Girvan for giving technical assistance on the scanning electron microscopy. We are grateful to Prof. Peter Lillford for his critical comments on this paper and Jane Wayte for proof reading this paper. Lee Fong Siow thanks the University of Otago for awarding the Dr. Sulaiman Daud Jubilee 125th Postgraduate Scholarships to carry out this work and the Postgraduate Publishing award during the preparation of this paper.
Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2008/12
Y1 - 2008/12
N2 - Cryo-responses of two types of large unilamellar vesicles (LUV) that were made from either egg yolk l-α-phosphatidylcholine (EPC) or 1,2-dipalmitoyl-rac-glycero-3-phosphocholine (DPPC), in the presence of non-permeable or permeable cryoprotective agents (CPA) was investigated. Partial ternary phase diagrams of CPA-salt-water with specific CPA to salt ratio (R), were constructed to estimate the phase volume of ice and unfrozen matrix of the LUV dispersion, which could aid in understanding the mechanistic actions of CPA. Leakage of both EPC and DPPC LUV was reduced if the sugar concentrations are above 10% (w/w) for disaccharides and 5% (w/w) for monosaccharides. Above these sugar concentrations, non-permeable CPA were more effective in preventing leakage of DPPC LUV than in EPC LUV. Below these sugar concentrations, EPC and DPPC LUV with limited mobility in the remaining unfrozen matrix were more likely to approach and interact with one and another, which were not anticipated when the LUV were completely embedded in the ice matrix. In the presence of Me2SO or EG, EPC LUV that had been subjected to freezing and thawing processes were protected from leakage. At room temperature, Me2SO and EG were detrimental to the DPPC LUV. This study suggests that the choice of CPA for cell cryopreservation depends on the type of phospholipids in plasma membranes, which vary in their acyl chain length and gel-liquid crystal phase transition temperature.
AB - Cryo-responses of two types of large unilamellar vesicles (LUV) that were made from either egg yolk l-α-phosphatidylcholine (EPC) or 1,2-dipalmitoyl-rac-glycero-3-phosphocholine (DPPC), in the presence of non-permeable or permeable cryoprotective agents (CPA) was investigated. Partial ternary phase diagrams of CPA-salt-water with specific CPA to salt ratio (R), were constructed to estimate the phase volume of ice and unfrozen matrix of the LUV dispersion, which could aid in understanding the mechanistic actions of CPA. Leakage of both EPC and DPPC LUV was reduced if the sugar concentrations are above 10% (w/w) for disaccharides and 5% (w/w) for monosaccharides. Above these sugar concentrations, non-permeable CPA were more effective in preventing leakage of DPPC LUV than in EPC LUV. Below these sugar concentrations, EPC and DPPC LUV with limited mobility in the remaining unfrozen matrix were more likely to approach and interact with one and another, which were not anticipated when the LUV were completely embedded in the ice matrix. In the presence of Me2SO or EG, EPC LUV that had been subjected to freezing and thawing processes were protected from leakage. At room temperature, Me2SO and EG were detrimental to the DPPC LUV. This study suggests that the choice of CPA for cell cryopreservation depends on the type of phospholipids in plasma membranes, which vary in their acyl chain length and gel-liquid crystal phase transition temperature.
KW - Cryoprotective agents (CPA)
KW - Dimethyl sulfoxide (MeSO)
KW - DPPC
KW - EPC
KW - Ethylene glycol (EG)
KW - Freeze-concentration
KW - Ice
KW - Large unilamellar vesicles (LUV)
KW - Sugars
KW - Unfrozen matrix
UR - http://www.scopus.com/inward/record.url?scp=56449094335&partnerID=8YFLogxK
U2 - 10.1016/j.cryobiol.2008.09.011
DO - 10.1016/j.cryobiol.2008.09.011
M3 - Article
C2 - 18854181
AN - SCOPUS:56449094335
SN - 0011-2240
VL - 57
SP - 276
EP - 285
JO - Cryobiology
JF - Cryobiology
IS - 3
ER -