Neat DODAB vesicles: Effect of sonication time on the phase transition thermodynamic parameters and its relation with incomplete chain freezing
Neat DODAB vesicles: Effect of sonication time on the phase transition thermodynamic parameters and its relation with incomplete chain freezing
复制标题
DOI：
10.1016/j.chemphyslip.2005.05.001
复制
发表时间：
2005-10-01
影响因子：
3.4
通讯作者：
Marques, EF
中科院分区：
文献类型：
--
作者：
Brito, RO;Marques, EF
在过去的20年里，由阳离子脂类双十八烷基二甲基溴化铵形成的囊泡溶液被广泛地用作膜系统的模型。通常，在文献中发现对于这些囊泡的凝胶-液晶(Gel-LC)相变的热力学参数存在差异。在这项工作中，我们系统地研究了超声方法对在正常水和氚水中制备的DODAB囊泡的主要转变温度和转变热的影响。结果表明，随着超声时间的延长，T-m和热值逐渐减小，直至达到平台值。当高度弯曲的囊泡冷却到转变温度以下时，这种效应与高度弯曲的囊泡中的不完全链结晶有关。用差示扫描量热仪(DSC)监测了老化对超声溶液的影响。(C)2005爱思唯尔爱尔兰有限公司。保留所有权利。
Vesicle solutions formed by the cationic lipid dioctadecyldimethylammonium bromide have been extensively used in the past 20 years as model membrane systems. Often, discrepancies are found in the literature for the thermodynamic parameters of the gel-to-liquid crystal (gel-lc) phase transition of these vesicles. In this work we present a systematic DSC investigation on the influence of the sonication method on the main temperature and enthalpy of the transition for DODAB vesicles, prepared both in normal and deuterated water. It is shown that as the sonication time increases, the T-m and enthalpy values decrease until a plateau value is reached. This effect is associated with incomplete chain crystallization in the highly curved vesicles (produced by sonication) when they are cooled below the transition temperature. The effect of aging on the sonicated solutions has also been monitored by DSC. (c) 2005 Elsevier Ireland Ltd. All rights reserved.