Ultrafast microfluidic mixer and freeze-quenching device
Ultrafast microfluidic mixer and freeze-quenching device
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DOI：
10.1021/ac0346205
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发表时间：
2003-10-15
影响因子：
7.4
通讯作者：
Yeh, SR
中科院分区：
文献类型：
--
作者：
Lin, Y;Gerfen, GJ;Yeh, SR
冷冻猝灭技术对于捕获快速化学或生化反应期间聚集的亚稳态中间体非常有用。然而，该技术的应用受到常规溶液混合器的长混合时间和低温流体的缓慢冷冻时间的限制。为了克服这些问题，我们已经设计和测试了一种新型的微流控硅混合器配备了一个新的冷冻淬火装置，与反应可以遵循到50 μ s。在微流控硅混合器，七个10微米直径的垂直支柱垂直于流动方向排列，并在450 pL的混合室交错的方式，以提高湍流混合。具有10 μ m × 100 μ m横截面的混合溶液射流以20 m/s的线流速从微流体硅混合器中离开。它在两个保持在77 K的旋转铜轮中的一个上瞬间冻结，随后被研磨成超细粉末。超细冷冻粉末具有优异的光谱质量和高填充因子，并且可以容易地在光谱观察池之间转移。通过叠氮化物和肌红蛋白在pH 5.0下的反应来测试微流体混合器。发现在混合器的混合死时间（20 μ s）内实现完全混合，并且确定该耦合装置的第一个可观察点为50 μ s，这类似于比市售仪器快2个数量级。
The freeze-quenching technique is extremely useful for trapping meta-stable intermediates populated during fast chemical or biochemical reactions. The application of this technique, however, is limited by the long mixing time of conventional solution mixers and the slow freezing time of cryogenic fluids. To overcome these problems, we have designed and tested a novel microfluidic silicon mixer equipped with a new freeze-quenching device, with which reactions can be followed down to 50 mus. In the microfluidic silicon mixer, seven 10-mum-diameter vertical pillars are arranged perpendicular to the flow direction and in a staggered fashion in the 450-pL mixing chamber to enhance turbulent mixing. The mixed-solution jet, with a cross section of 10 mum x 100 mum, exits from the microfluidic silicon mixer with a linear flow velocity of 20 m/s. It instantaneously freezes on one of two rotating copper wheels maintained at 77 K and is subsequently ground into an ultrafine powder. The ultrafine frozen powder exhibits excellent spectral quality and high packing factor and can be readily transferred between spectroscopic observation cells. The microfluidic mixer was tested by the reaction between azide and myoglobin at pH 5.0. It was found that complete mixing was achieved within the mixing dead time of the mixer (20 mus), and the first observable point for this coupled device was determined to be 50 mus, which is similar to2 orders of magnitude faster than commercially available instruments.