Ultrafast microfluidic mixer with three-dimensional flow focusing for studies of biochemical kinetics
Ultrafast microfluidic mixer with three-dimensional flow focusing for studies of biochemical kinetics
复制标题
DOI：
10.1039/b914174j
复制
发表时间：
2010-01-01
期刊：
影响因子：
6.1
通讯作者：
Groisman, Alex
中科院分区：
文献类型：
--
作者：
Gambin, Yann;Simonnet, Claire;Groisman, Alex
生化反应动力学的研究，特别是蛋白质和RNA的折叠，对于理解活细胞中生物分子和过程的功能非常重要。许多生物化学反应发生迅速，因此需要在很短的时间尺度上触发它们的动力学研究，这通常是通过在湍流中混合来完成的。在微流体装置中的层流中实现更快速和样品有效的混合，其中样品被二维（2D）聚焦成薄片。在这里，我们描述的设计和操作的超快微流体混合器与三维（3D）流动聚焦。将3D聚焦样品限制在微通道中间附近的窄流中，使其速度几乎均匀，并且可以在不排除样品任何部分的情况下监测反应动力学。因此，样品消耗大大减少，并且可以在没有共焦设置的情况下监测样品的荧光。此外，3D聚焦允许使用基于落射荧光成像的专门开发的技术以高空间分辨率容易地测量样品的速度。速度与位置的数据用于精确校准位置与反应时间之间的转换，这对于精确的动力学测量至关重要。该设备在10 μ s的规模上进行混合，这与具有2D聚焦的层流混合器相当。与以前的超快层流混合器不同，其在硬质材料中加工，本微流体装置由聚（二甲基硅氧烷）PDMS的单铸件制成，因此制造更简单且更便宜。
Studies of the kinetics of biochemical reactions, especially of folding of proteins and RNA, are important for understanding the function of biomolecules and processes in live cells. Many biochemical reactions occur rapidly and thus need to be triggered on very short time scales for their kinetics to be studied, which is often accomplished by mixing in a turbulent flow. More rapid and sample-efficient mixing is achieved in laminar flow in a microfluidic device, in which the sample is two-dimensionally (2D) focused to a thin sheet. Here we describe the design and operation of an ultrafast microfluidic mixer with three-dimensional (3D) flow focusing. The confinement of a 3D-focused sample to a narrow stream near the middle of a microchannel renders its velocity nearly uniform and makes it possible to monitor the reaction kinetics without exclusion of any parts of the sample. Hence, the sample consumption is substantially reduced and the fluorescence of the sample can be monitored without a confocal setup. Moreover, the 3D-focusing allows facile measurements of velocity of the sample with a high spatial resolution using a specially developed technique based on epi-fluorescence imaging. The data on the velocity vs. position are used to precisely calibrate the conversion between position and the reaction time, which is essential for accurate kinetic measurements. The device performs mixing on a 10 mu s scale, which is comparable to that of the laminar mixers with 2D focusing. Unlike previous ultrafast laminar mixers, which were machined in hard materials, the present microfluidic device is made of a single cast of poly(dimethylsiloxane), PDMS, and is thus simpler and less expensive to manufacture.