3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex
3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex
复制标题
基于 3D 流体动力流动聚焦的微混合器可实现高分辨率成像，用于研究 G-四链体的早期折叠动力学
DOI：
10.1016/j.snb.2019.05.026
复制
发表时间：
2019-08-15
影响因子：
8.4
通讯作者：
Yang, Yunhuang
中科院分区：
文献类型：
--
作者：
Hu, Rui;Liu, Chao;Yang, Yunhuang
基于流体动力学流动聚焦的微混合器（层流微混合器）已广泛应用于生物大分子折叠动力学的研究，因为它们能够在微秒时间尺度上解析折叠事件。尽管大多数现有的层流微混合器试图减少混合时间，但我们的工作重点是开发一种能够在更稳定的流动下产生高分辨率图像的系统，从而实现更准确的动力学分析。具体而言，我们开发了一种简单的三维（3D）层流微混合器，它将样品流分布为3D轮廓，以解决二维混合器中迪恩涡旋引起的流动不稳定问题。在3D混合器中，样品流在约200纳米/像素的分辨率下成功聚焦到一个像素宽度，这接近光学显微镜的分辨率，代表了使用3D混合器所达到的最高成像分辨率。此外，我们利用该装置研究了在不同钠离子浓度下G - 四链体的早期折叠动力学。有趣的是，在折叠过程的指数阶段之前发现了一个滞后阶段。而且，我们得到了在50 mM、100 mM和200 mM NaCl条件下，G - 四链体的观测动力学分别为(1.51 ± 0.02)×10⁴ s⁻¹、(1.68 ± 0.04)×10⁴ s⁻¹和(2.01 ± 0.02)×10⁴ s⁻¹。
Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of (similar to)200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex's observed kinetics of (1.51 +/- 0.02) x 10(4 )s(-1), (1.68 +/- 0.04) x 10(4 )s(-1) and (2.01 +/- 0.02) x 10(4) s(-1) at 50-, 100- and 200 mM NaCl, respectively.