Thermal and structural behavior of dioctadecyldimethylammonium bromide dispersions studied by differential scanning calorimetry and X-ray scattering.
Thermal and structural behavior of dioctadecyldimethylammonium bromide dispersions studied by differential scanning calorimetry and X-ray scattering.
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DOI：
10.1371/journal.pone.0044702
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Malmsten M
中科院分区：
文献类型：
--
作者：
Feitosa E;Adati RD;Hansson P;Malmsten M
双十八烷基二甲基溴化铵(DODAB)是一种双链阳离子脂类，在水溶液中以双层结构组装。形成的精确结构取决于例如脂类浓度和温度。我们在这里结合差示扫描量热仪(DSC)和X射线散射(SAXS和WAXS)研究了在1-70°C温度范围内高达120 mm的DODAB在水中的热行为和结构行为，在1 mm以下，该体系以单层囊泡(ULV)为主。在1~65 mm之间，ULV和多层结构(MLSS)共存，而在65 mm以上，MLSS是首选结构。根据温度的不同，差示扫描量热法和X射线衍射法表明，囊泡可以处于亚凝胶(SG)、凝胶或液晶(LC)状态，而MLSS(晶格距离d = 为36.7o)则由处于SG状态的交错的片层和处于LC状态(无Bragg峰)的ULV组成。报道了在加热和冷却模式下得到的与这些双层结构的热转变有关的临界温度，以及相应的转变热。
Dioctadecyldimethylammonium bromide (DODAB) is a double chain cationic lipid, which assembles as bilayer structures in aqueous solution. The precise structures formed depend on, e.g., lipid concentration and temperature. We here combine differential scanning calorimetry (DSC) and X-ray scattering (SAXS and WAXS) to investigate the thermal and structural behavior of up to 120 mM DODAB in water within the temperature range 1–70°C. Below 1 mM, this system is dominated by unilamellar vesicles (ULVs). Between 1 and 65 mM, ULVs and multilamellar structures (MLSs) co-exist, while above 65 mM, the MLSs are the preferred structure. Depending on temperature, DSC and X-ray data show that the vesicles can be either in the subgel (SG), gel, or liquid crystalline (LC) state, while the MLSs (with lattice distance d = 36.7 Å) consist of interdigitated lamellae in the SG state, and ULVs in the LC state (no Bragg peak). Critical temperatures related to the thermal transitions of these bilayer structures obtained in the heating and cooling modes are reported, together with the corresponding transition enthalpies.
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影响因子：
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