Spectrally resolved flow imaging of fluids inside a microfluidic chip with ultrahigh time resolution
Spectrally resolved flow imaging of fluids inside a microfluidic chip with ultrahigh time resolution
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DOI：
10.1016/j.jmr.2008.04.037
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发表时间：
2008-08-01
影响因子：
2.2
通讯作者：
Pines, Alex
中科院分区：
文献类型：
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作者：
Harel, Elad;Pines, Alex
微流控已经发展成为一个完整的芯片实验室平台，应用于许多科学研究领域。虽然光学技术主要用作检测模式，但磁共振(MR)因其非侵入性操作和分析保真度而成为一种潜在的强大和补充工具。目前两个普遍存在的限制限制了磁共振技术在微流控设备上的应用：低灵敏度和可探测的动力学相对较慢的时间尺度。通常认为，观察一个变量的时间尺度限制了人们测量互补变量的确定性。例如，短的观测时间意味着较低的光谱分辨率。在这篇文章中，我们展示了一种新的方法，它克服了这一基本限制，原则上允许任意高的时间分辨率，整个微流控设备的灵敏度比直接MR测量大几个数量级。通过记录通过复杂的3D微流控设备以每秒500帧的速度记录化学分解的流体混合，证明了这种增强，这是磁共振成像实验中记录的最高速度。这一发展的关键是将远程探测与对其空间编码的对应对象进行时间“切片”相结合。远程检测避免了在微流控设备上直接检测MR的不灵敏问题，相对于传统的核磁共振，直接灵敏度小于10(-5)，而时间切片通过使用磁场梯度将时间变量转换为空间变量，消除了有限观测时间的限制。这种方法对观察快速过程，如流体混合、快速结合和某些类型的化学反应具有亚毫秒级的时间分辨率，并作为一种新的芯片上层析方法。由爱思唯尔公司出版。
Microfluidics has advanced to become a complete lab-on-a-chip platform with applications across Many disciplines of scientific research. While optical techniques are primarily used as modes of detection, magnetic resonance (MR) is emerging as a potentially powerful and complementary tool because of its non-invasive operation and analytical fidelity. Two prevailing limitations Currently inhibit MR techniques on microfluidic devices: poor sensitivity and the relatively slow time scale of dynamics that can be probed. it is commonly assumed that the time scale of observation of one variable limits the certainty with which one can measure the complementary variable. For example, short observation times imply poor spectral resolution. In this article, we demonstrate a new methodology that overcomes this fundamental limit, allowing in principle for arbitrarily high temporal resolution with a sensitivity across the entire microfluidic device several Orders of magnitude greater than is possible by direct MR measurement. The enhancement is evidenced by recording chemically resolved fluid mixing through a complex 3D microfluidic device at 500 frames per second, the highest recorded in a magnetic resonance imaging experiment. The key to this development is combining remote detection with a time 'slicing' of its spatially encoded counterpart. Remote detection circumvents the problem of insensitive direct MR detection on a microfluidic device where the direct sensitivity is less than 10(-5) relative to traditional NMR, while the time slicing eliminates the constraints of the limited observation time by converting the time variable into a spatial variable through the use of magnetic field gradients. This method has implications for observing fast processes, Such as fluid mixing, rapid binding, and certain classes of chemical reactions with sub millisecond time resolution and as a new modality for on-chip chromatography. Published by Elsevier Inc.