Trapping single small molecules in solution

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。哈佛大学的Adam E. Cohen教授开发了一种能够抑制溶液中单个小分子布朗运动的陷阱，分子直径小至1nm，并获得了实验物理化学计划的奖励。该陷阱结合了光子对光子的跟踪和实时电动力学反馈，以诱导电动力学运动，从而抵消一个分子的布朗运动。科恩实验室将研究努力逃离陷阱的分子的随机布朗跳跃，以及分子对电动和光学扰动的反应。研究人员的目标是开发一个平台，通过该平台，几乎任何荧光或荧光标记的分子都可以在单分子水平上进行研究，而无需依赖于表面的化学固定。该陷阱将用于研究单个DNA小分子的弯曲动力学。许多生物分子在单分子水平上表现出比在整体、整体平均实验中观察到的更为复杂的行为。这种复杂性来自于与原子的不同构型相对应的动态异质性。通常稀疏分布的分子亚态对生物功能很重要。由于布朗运动的结果，分子在自由溶液中不能保持静止，而表面固定化可能会破坏分子的功能，因此逐个研究生物分子的任务变得复杂。目前的研究有望增加可以在单分子水平上研究的分子范围。这项研究结合了纳米制造、光学、微流体、电子学、计算机编程和生物化学。参与该项目的学生和博士后将获得所有这些不同领域的经验。此外，高中生将在暑假里制作陷阱。这项研究的结果将通过公开讲座和互联网上的录象以及传统的科学出版物广泛传播。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Professor Adam E. Cohen of Harvard University is supported by an award from the Experimental Physical Chemistry Program to develop a trap capable of suppressing the Brownian motion of single small molecules in solution, with molecular diameters as small as 1 nm. The trap combines photon-by-photon tracking and real-time electrokinetic feedback to induce an electrokinetic motion that cancels the Brownian motion of one molecule. The Cohen Lab will study the random Brownian jumps of a molecule struggling to escape from the trap, as well as the responses of a molecule to electrokinetic and optical perturbations. The researchers' goal is to develop a platform via which nearly any fluorescent or fluorescently labeled molecule can be studied at the single-molecule level, without relying on chemical immobilization on a surface. The trap will be used to study the bending dynamics of single small molecules of DNA.Many biomolecules show strikingly more complex behavior at the single-molecule level than is observable in bulk, ensemble-averaged experiments. This complexity arises from dynamic heterogeneity corresponding to distinct configurations of the atoms. Often sparsely populated molecular sub-states are important for the biological function. The task of studying biomolecules one-by-one is complicated by the fact that the molecules do not hold still in free solution, a consequence of Brownian motion, while surface immobilization may disrupt the molecular function. The present research promises to increase the range of molecules that can be studied at the single-molecule level. This research combines nanofabrication, optics, microfluidics, electronics, computer programming, and biochemistry. The student and postdoc working on the project will gain experience in all of these diverse areas. In addition, high school students will spend summers working on the trap. Results of the research will be widely disseminated in public lectures and videos available on the Internet, as well as conventional scientific publications.