Novel perspectives for the application of total internal reflection microscopy.
Novel perspectives for the application of total internal reflection microscopy.
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DOI：
10.1364/oe.17.023975
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发表时间：
2009-09
期刊：
影响因子：
3.8
通讯作者：
G. Volpe;T. Brettschneider;L. Helden;C. Bechinger
中科院分区：
文献类型：
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作者：
G. Volpe;T. Brettschneider;L. Helden;C. Bechinger
全内反射显微镜 (TIRM) 是一种灵敏的非侵入性技术，用于以飞牛顿分辨率测量胶体颗粒与墙壁之间的相互作用势。对粒子壁分离距离 z 的平衡分布进行采样，监测瞬逝照明下布朗粒子散射的强度 I。数据分析的核心是了解 I 和相应 z 之间的关系，通常必须事先知道该关系。这对应用 TIRM 的实验条件（倏逝波的短穿透深度、透明表面）造成了相当大的限制。在这里，我们介绍了一种仅依靠距离相关的粒子壁流体动力学相互作用来通过实验确定 I(z) 的方法。我们证明，这种方法极大地扩展了 TIRM 可用的条件范围，甚至允许在高反射金表面上进行测量，其中多次反射会导致复杂的 (z)。
Total Internal Reflection Microscopy (TIRM) is a sensitive non-invasive technique to measure the interaction potentials between a colloidal particle and a wall with femtonewton resolution. The equilibrium distribution of the particle-wall separation distance z is sampled monitoring the intensity I scattered by the Brownian particle under evanescent illumination. Central to the data analysis is the knowledge of the relation between I and the corresponding z, which typically must be known a priori. This poses considerable constraints to the experimental conditions where TIRM can be applied (short penetration depth of the evanescent wave, transparent surfaces). Here, we introduce a method to experimentally determine I(z) by relying only on the distance-dependent particle-wall hydrodynamic interactions. We demonstrate that this method largely extends the range of conditions accessible with TIRM, and even allows measurements on highly reflecting gold surfaces where multiple reflections lead to a complex (z).