Relaxation process and dynamic heat capacity at the main transition of multi-lamellar vesicles of phosphatidylcholines

磷脂酰胆碱多层囊泡主转变的弛豫过程和动态热容

• 批准号: 08454111
• 负责人: EMA Kenji
• 金额: $ 3.97万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454111/
• 关键词: phospholipid; phase transition; relaxation process; dynamic heat capacity

At the first stage of the research, the unilamellar vasicle samples with various alkyl chain length have been studied. For the measurements with chain length from 12 to 15, it was found that the heat anomaly accompanying the transition depends significantly on the chain length. It was also found that the unilamellar sample with chain length 12 shows an intermediate phase, which is similar to the multilamellar sample with the same chain length. A detailed analysis of these results has revealed that the observed chain-length dependence of the anomaly can be described with the modified Izuyama-Akutsu theory which has been proposed by the present authors to explain the vesicle-size dependence of the heat anomaly. It is expected from this modified theory that we can reach a critical point by adjusting the vesicle size and the chain length. We found that the sample with 30 nm diameter with chain length 15 is close to the critical point. A preliminary analysis shows that the critical exponent has a value alpha=0.5-0.7. More detailed analyzes are in progress. Although the measurement on multilamellar vesicles is behind the schedule, the results on unimalellar vesicles described above serve as a good background for future studies both on unilamellar and multilamellar vesicles.

在研究的第一阶段，研究了具有不同烷基链长度的单层血管样品。对于链长从12到15的测量，发现伴随转变的热异常显着取决于链长。还发现链长为12的单层样品显示出中间相，这与具有相同链长的多层样品相似。对这些结果的详细分析表明，观察到的异常链长依赖性可以用修正的 Izuyama-Akutsu 理论来描述，该理论是由本作者提出的，用于解释热异常的囊泡大小依赖性。从这个修改的理论中预计我们可以通过调整囊泡大小和链长度来达到临界点。我们发现直径为30 nm、链长为15的样品接近临界点。初步分析表明，临界指数的值为α=0.5-0.7。更详细的分析正在进行中。尽管多层囊泡的测量落后于计划，但上述单层囊泡的结果为未来单层和多层囊泡的研究提供了良好的背景。

项目成果

K.Uchida, H.Yao, and K.Ema: "Effect of chain length on the heat-cpacity anomaly at the gel to liquid-crysalline phase transition in unilamellar vesicles of phosphatidylcholines" Phys.Rev.E. 56. 661-666 (1997)

K.Uchida、H.Yao 和 K.Ema：“链长对磷脂酰胆碱单层囊泡中凝胶到液晶相变热容量异常的影响”Phys.Rev.E。

Haruhiko Yao et al.: "Nonadiabatic scanning calorimeter" Rev.Sci.Instrum.69. 172-178 (1998)

Haruhiko Yao 等人：“非绝热扫描量热计”Rev.Sci.Instrum.69。

H.Yao, K.Ema, and C.W.Garland: "Nonadiabatic scanning calorimeter" Rev.Sci.Instrum.69. 172-178 (1998)

H.Yao、K.Ema 和 C.W.Garland：“非绝热扫描量热计”Rev.Sci.Instrum.69。

Koji Uchida et al.: "Fffect of chain length on the heat-capacity anomaly at the gel to liquid-crystalline phase transition in unilamellar vesicles of phosphatidylcholines" Phys.Rev.E. 56. 661-666 (1997)

Koji Uchida 等人：“链长对磷脂酰胆碱单层囊泡中凝胶到液晶相变热容异常的影响”Phys.Rev.E。

Koji Uchida: "Effect of chain length on the heat-capacity anomaly at the gel to liquid-crystalline phase transition in unilamellar vesicles of phosphafidylcholines" Physical Review E. 56・1. 661-666 (1997)

Koji Uchida：“链长对磷脂酰胆碱单层囊泡中凝胶到液晶相转变时热容量异常的影响”物理评论 E. 56・1（1997）。