Hasegawa Takeshi, Moriya Daisuke, Kakuda Hiroyuki, Li Changqing, Orbulescu Jhony, Leblanc Roger M
Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, 1-1-2 Izumi-cho, Narashino 275-8575, Japan.
J Phys Chem B. 2005 Jul 7;109(26):12856-60. doi: 10.1021/jp051732m.
The fibril formation process of a synthetic peptidolipid compound in a Langmuir monolayer at the air-water interface has been analyzed by surface pressure and surface dipole moment-area isotherms, followed by infrared spectral analysis of related Langmuir-Blodgett films. Thus far, the analysis of randomly oriented molecular assemblies has been a difficult matter, especially for spectroscopic measurements. In the present study, the Langmuir film isotherms were discussed in detail, and they have readily been correlated to the infrared spectra. For the spectral analysis, infrared multiple-angle incidence resolution spectroscopy (MAIRS) was employed, which was compared to the results by conventional techniques. Since the peptide assemblies greatly responded to a metal surface, the reflection-absorption technique was not useful for our analysis. Instead, MAIRS was found to be powerful to reveal the anisotropic structure of the Langmuir films, and a disordered molecular architecture has been revealed via the molecular orientation analysis. As a result, the fibril-like aggregation formation process during the monolayer compression, which was suggested by previous topographical study, has been found to be due to the stiff domain formation in the Langmuir films.
通过表面压力和表面偶极矩-面积等温线，随后对相关的朗缪尔-布洛杰特膜进行红外光谱分析，研究了一种合成肽脂化合物在空气-水界面的朗缪尔单分子层中的原纤维形成过程。到目前为止，对随机取向的分子聚集体进行分析一直是一件困难的事情，特别是对于光谱测量。在本研究中，详细讨论了朗缪尔膜等温线，并将其与红外光谱进行了很好的关联。对于光谱分析，采用了红外多角度入射分辨光谱（MAIRS），并与传统技术的结果进行了比较。由于肽聚集体对金属表面有很大的响应，反射吸收技术对我们的分析没有用。相反，发现MAIRS对于揭示朗缪尔膜的各向异性结构很有效，并且通过分子取向分析揭示了无序的分子结构。结果发现，如先前地形学研究所表明的，在单分子层压缩过程中形成的原纤维状聚集过程是由于朗缪尔膜中刚性域的形成。
