Three-dimensional molecular mapping of a multiple emulsion by means of CARS microscopy.
Three-dimensional molecular mapping of a multiple emulsion by means of CARS microscopy.
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通过 CARS 显微镜对多重乳液进行三维分子图谱。
DOI：
10.1021/jp709643h
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
J. Popp
中科院分区：
文献类型：
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作者：
T. Meyer;D. Akimov;N. Tarcea;Susana Chatzipapadopoulos;G. Muschiolik;Jens Kobow;M. Schmitt;J. Popp
由分散在含有乳化剂的油相中的水滴组成的多重乳液，所述乳化剂在外部水相中乳化（W/O/W），在用于开发新药的药理学中、在用于设计功能性食品的营养科学中、以及在生物学中作为细胞器如脂质体的模型系统引起极大兴趣。在食品工业中，水相中具有高糖含量的多重乳液可用于糖果的生产，因为高糖含量防止变质。然而，对于这些乳液，油相和水相的折射率非常相似。这严重阻碍了对这些乳剂的分析，例如，因为基于透射或反射的显微技术不能提供足够的对比度。采用显微拉曼光谱对具有相同折射率的浓W/O/W乳状液的内分散相进行了表征，并利用三维激光扫描汽车（相干反斯托克斯拉曼散射）显微镜研究了水-油-水乳状液的组成和分子分布。汽车显微镜已被用于研究分散在油滴中的水滴在不同的拉曼共振可视化不同的分子种类。可以清楚地看到直径约700 nm的水滴。汽车显微镜研究这个特定的系统的优势强调通过比较这种显微技术与传统的共焦反射和透射显微镜。
Multiple emulsions consisting of water droplets dispersed in an oil phase containing emulsifier which is emulsified in an outer water phase (W/O/W) are of great interest in pharmacology for developing new drugs, in the nutrition sciences for designing functional food, and in biology as model systems for cell organelles such as liposomes. In the food industry multiple emulsions with high sugar content in the aqueous phase can be used for the production of sweets, because the high sugar content prevents deterioration. However, for these emulsions the refractive indexes of oil and aqueous phase are very similar. This seriously impedes the analysis of these emulsions, e.g., for process monitoring, because microscopic techniques based on transmission or reflection do not provide sufficient contrast. We have characterized the inner dispersed phase of concentrated W/O/W emulsions with the same refractive index of the three phases by micro Raman spectroscopy and investigated the composition and molecular distribution in water-oil-water emulsions by means of three-dimensional laser scanning CARS (coherent anti-Stokes Raman scattering) microscopy. CARS microscopy has been used to study water droplets dispersed in oil droplets at different Raman resonances to visualize different molecular species. Water droplets with a diameter of about 700 nm could clearly be visualized. The advantages of CARS microscopy for studying this particular system are emphasized by comparing this microscopic technique with conventional confocal reflection and transmission microscopies.