Imaging of flow patterns with fluorescent molecular rotors.
Imaging of flow patterns with fluorescent molecular rotors.
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DOI：
10.1007/s10895-010-0661-x
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发表时间：
2010-09
影响因子：
2.7
通讯作者：
Haidekker, Mark A.
中科院分区：
文献类型：
--
作者：
Mustafic, Adnan;Huang, Hsuan-Ming;Theodorakis, Emmanuel A.;Haidekker, Mark A.
关键词：
分子转子是一组荧光分子，在光激发时形成扭曲的分子内电荷转移态（TICT）。某些类型的分子转子，其中包括基于亚苄基丙二腈基序的分子转子，通过非辐射分子内旋转或通过荧光发射返回基态。在低粘度溶剂中，分子内旋转占主导地位，荧光量子产率较低。较高的溶剂粘度会降低分子内旋转速率，从而提高量子产率。我们最近描述了一种不同的机制，分子转子的荧光量子产率也取决于溶剂的剪切应力。在这项研究中，我们研究了剪切敏感分子转子在流体室中对流型进行成像的可能应用。具有不同几何形状的流动室由聚碳酸酯或丙烯酸制成。将分子转子的乙二醇溶液在受控流速下注入腔室中。使用数码相机拍摄流动室的 LED 诱导荧光 (LIF) 图像，将流动图像和无流动图像之间的强度差异可视化，并与计算流体动力学 (CFD) 模拟进行比较。平均流速低至 0.1 mm/s 时即可检测到强度差异，并且发现流速与强度增加之间存在指数关联。此外，还发现与计算流体动力学模拟具有良好的定性匹配。另一方面，长时间暴露在光下会降低发射强度。凭借其高灵敏度和高空间和时间分辨率，利用分子转子对流型进行成像可能成为微流体、流量测量和控制中的有用工具。
Molecular rotors are a group of fluorescent molecules that form twisted intramolecular charge transfer states (TICT) upon photoexcitation. Some classes of molecular rotors, among them those that are built on the benzylidene malononitrile motif, return to the ground state either by nonradiative intramolecular rotation or by fluorescence emission. In low-viscosity solvents, intramolecular rotation dominates, and the fluorescence quantum yield is low. Higher solvent viscosities reduce the intramolecular rotation rate, thus increasing the quantum yield. We recently described a different mechanism whereby the fluorescence quantum yield of the molecular rotor also depends on the shear stress of the solvent. In this study, we examined a possible application for shear-sensitive molecular rotors for imaging flow patterns in fluidic chambers. Flow chambers with different geometries were constructed from polycarbonate or acrylic. Solutions of molecular rotors in ethylene glycol were injected into the chamber under controlled flow rates. LED-induced fluorescence (LIF) images of the flow chambers were taken with a digital camera, and the intensity difference between flow and no-flow images was visualized and compared to computed fluid dynamics (CFD) simulations. Intensity differences were detectable with average flow rates as low as 0.1 mm/s, and an exponential association between flow rate and intensity increase was found. Furthermore, a good qualitative match to computed fluid dynamics simulations was seen. On the other hand, prolonged exposure to light reduced the emission intensity. With its high sensitivity and high spatial and temporal resolution, imaging of flow patterns with molecular rotors may become a useful tool in microfluidics, flow measurement, and control.
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影响因子：
3.3
作者：
Allen, BD;Benniston, AC;Yu, CF
通讯作者：
Yu, CF
影响因子：
3.2
作者：
Haidekker, Mark A.;Theodorakis, Emmanuel A.
通讯作者：
Theodorakis, Emmanuel A.
DOI：
10.1152/ajpheart.00712.2001
发表时间：
2002-05-01
影响因子：
4.8
作者：
Haidekker, MA;Tsai, AG;Intaglietta, M
通讯作者：
Intaglietta, M
影响因子：
--
作者：
LOUTFY, RO;LAW, KY
通讯作者：
LAW, KY
影响因子：
--
作者：
Haidekker, MA;Akers, W;Theodorakis, EA
通讯作者：
Theodorakis, EA