Strong Concentration Enhancement of Molecules at the Interface of Aqueous Microdroplets
Strong Concentration Enhancement of Molecules at the Interface of Aqueous Microdroplets
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DOI：
10.1021/acs.jpcb.0c07718
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发表时间：
2020-11-05
影响因子：
3.3
通讯作者：
Min, Wei
中科院分区：
文献类型：
--
作者：
Xiong, Hanqing;Lee, Jae Kyoo;Min, Wei
水可以说是地球上最常见但最不为人所知的物质。水和疏水介质（如空气、油或脂质）之间的界面在化学和生物学中起着重要作用。然而，在这样的介质中的微米尺寸的水滴（微滴）的界面处的分子的行为是很差的特征。本文采用双光子荧光显微镜和福斯特共振能量转移成像技术，以高对比度和高分辨率研究了探针在水-油微滴中的定位。我们发现水溶性探针存在表面富集和取向排列的一般效应。值得注意的是，探针被集中到一个类似的10 nm的薄层在微滴水-油界面高达10 000倍相比，散装对应。我们认为，水溶性分子的强烈富集和排列，可能是由界面处的局部电场部分诱导的，可能是占在含水微滴中观察到的数量级更快的反应速率的一个主要因素，与它们的散装对应物相比。
Water is arguably the most common and yet least understood material on Earth. The interface between water and a hydrophobic medium, such as air, oil, or lipids, plays a fundamental role in chemistry and biology. However, the behavior of molecules at interface of micron-sized water droplets (microdroplets) in such media is poorly characterized. Herein we employed two-photon fluorescence microscopy and Forster resonant energy transfer imaging to study the probe localization in water-oil microdroplets with high contrast and resolution. We found that there exists a general effect of surface enrichment and orientation alignment for water-soluble probes. Remarkably, probes are concentrated into a similar to 10 nm thin layer at the microdroplet water-oil interface by up to 10 000-fold compared to the bulk counterpart. We suggest that the strong enrichment and alignment of water-soluble molecules, likely to be induced in part by a local electric field at the interface, could be a major factor accounting for orders of magnitude faster reaction rates observed in aqueous microdroplets compared to their bulk counterparts.