Optimal strategy for trapping single fluorescent molecules in solution using the ABEL trap.
Optimal strategy for trapping single fluorescent molecules in solution using the ABEL trap.
复制标题
使用 ABEL 陷阱捕获溶液中单个荧光分子的最佳策略。
DOI：
10.1007/s00340-009-3843-y
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Moerner,WE
中科院分区：
文献类型：
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作者：
Wang,Q;Moerner,WE
利用高速位置传感和反布朗电动(ABEL)陷阱中的电动反馈力，实现了对溶液中10 nm单荧光生物分子的捕获。小物体在溶液中的高扩散系数要求非常快速、实时地检测位置，这以前是通过简单的旋转光束实现的，但对于最小的物体，如单个纳米尺寸的荧光分子，需要改进策略。同时，单个分子的光子发射率和光子总数都受到限制，因此必须尽可能高效地利用每个发射的光子。我们描述了一种新的Abel陷阱控制器设计，其特点是在2D正方形格子上对激励波束进行快速骑士巡回扫描，并采用基于卡尔曼滤波的估计器进行最优位置检测。这一策略直接导致了一种基于最大似然的方法来提取陷阱中保持的对象的扩散系数。通过蒙特卡罗模拟验证了算法的有效性，并与简单的旋转梁设计进行了比较。我们的新方法产生了更紧密的陷阱和更好的提取扩散系数的能力。
Trapping of 10-nm-sized single fluorescent bio-molecules in solution has been achieved using high-speed position sensing and electrokinetic feedback forces in the Anti-Brownian ELectrokinetic (ABEL) trap. The high diffusion coefficient of small objects in solution requires very fast, real-time sensing of position, and this has been previously achieved using a simple rotating beam, but improved strategies are needed for the smallest objects, such as single nanometer-sized fluorescent molecules. At the same time, single molecules are limited in photon emission rate and total number of photons, so each emitted photon must be used as efficiently as possible. We describe a new controller design for the ABEL trap which features fast, knight’s tour scanning of an excitation beam on a 2D square lattice and a Kalman filter-based estimator for optimal position sensing. This strategy leads directly to a maximum-likelihood-based method to extract the diffusion coefficient of the object held in the trap. The effectiveness of the algorithms are demonstrated and compared to the simple rotating beam design through Monte Carlo simulations. Our new approach yields tighter trapping and a much improved ability to extract diffusion coefficients.