Microfabricated sieve for the continuous sorting of macromolecules
Microfabricated sieve for the continuous sorting of macromolecules
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DOI：
10.1103/physrevlett.80.1552
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发表时间：
1998-02
影响因子：
8.6
通讯作者：
T. Duke;R. Austin
中科院分区：
文献类型：
--
作者：
T. Duke;R. Austin
分离和分析生物大分子混合物的不同成分的有效方法对于研究和生物医学应用都至关重要。为了满足这一需求，人们正在共同努力，利用微加工技术开发小型化生物分析设备[1]。这些设备旨在取代目前耗时且难以自动化的方法。例如，DNA 分子的分离目前是通过凝胶电泳完成的 [2]；不同大小的分子在凝胶中以不同的速度迁移，经过一定时间后可以彼此区分。使用凝胶筛分 DNA（这是必要的，因为游离溶液中的电泳迁移率 m0 与大小无关）使程序变得复杂：每次都必须制备新的基质，并且 DNA 的回收很困难，因为必须对凝胶进行切片或印迹 [2]。在这封信中，我们基于 Volkmuth 和 Austin [3] 引入的微制造阵列技术，提出了一种分离生物大分子的新方法。光刻用于在硅芯片上蚀刻障碍物图案，然后将其密封以制成准二维“筛子”，分子溶液可以通过该筛子进行电泳。与凝胶相比，一个明显的优点是筛子的规则性。然而，主要的优点是可以随意选择障碍物的图案。这提供了一种电泳分离的替代方法。通过设置障碍物使得分子偏离场方向，可以在横向于场的方向上实现分离。一般来说，这可以通过选择周期性障碍物阵列来完成，每个障碍物相对于场方向的反射都是不对称的。空间不对称性和破坏的时间反转对称性（由流动造成）的结合导致分子的布朗运动得到纠正。由于该效应取决于热运动，因此具有不同扩散系数的分子会偏转不同的量，因此会产生混合
Efficient methods to separate and analyze the different components of a mixture of biological macromolecules are of paramount importance, both for research and in biomedical applications. To meet this need, a concerted effort is being made to develop miniaturized bioanalytical devices [1], using the technology of microfabrication. These devices aim to supersede the present methods, which are time consuming and difficult to automate. The separation of DNA molecules, for example, is currently accomplished by gel electrophoresis [2]; molecules of different size migrate at different speeds through the gel, and can be distinguished from one another after a certain time has elapsed. Using a gel to sieve the DNA (a necessity, since the electrophoretic mobility m0 in free solution is independent of size) complicates the procedure: A new matrix must be made each time, and recovery of the DNA is awkward, since the gel must either be sliced or blotted [2]. In this Letter, we propose a fresh approach to separating biological macromolecules, based on the technology of microfabricated arrays introduced by Volkmuth and Austin [3]. Lithography is used to etch a pattern of obstacles on a silicon chip, which is then sealed to make a quasi-two-dimensional “sieve” through which a solution of molecules can be electrophoresed. One obvious benefit compared to gels is the regularity of the sieve. The major advantage, however, is that the pattern of obstacles can be chosen at will. This allows an alternative method of electrophoretic separation. By disposing the obstacles so that the molecules are deflected away from the field direction, a separation can be effected in the direction transverse to the field. Quite generally, this can be done by choosing a periodic array of obstacles, each of which is asymmetric with respect to reflection in the field direction. The combination of the spatial asymmetry and the broken time-reversal symmetry (imposed by the flow) causes the Brownian motion of the molecules to be rectified. Since the effect depends on the thermal motion, molecules with different diffusion coefficients are deflected by different amounts, and, consequently, a mix