Focused Orientation and Position Imaging (FOPI) of Single Anisotropic Plasmonic Nanoparticles by Total Internal Reflection Scattering Microscopy
Focused Orientation and Position Imaging (FOPI) of Single Anisotropic Plasmonic Nanoparticles by Total Internal Reflection Scattering Microscopy
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DOI：
10.1021/nl301972t
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发表时间：
2012-08-01
期刊：
影响因子：
10.8
通讯作者：
Fang, Ning
中科院分区：
文献类型：
--
作者：
Ha, Ji Won;Marchuk, Kyle;Fang, Ning
以各向异性金纳米棒为取向探针的离焦定向和位置成像技术（DOPI）和基于偏振的聚焦成像技术已被广泛用于检测旋转运动。然而，这些技术有许多明显的局限性，例如失焦aunr的信号强度大大降低，相对较低的空间和时间分辨率，以及焦内aunr的角退化。在此，我们提出了一种基于全内反射（TIR）散射的聚焦定向和位置成像（FOPI）技术，该技术支持在50 nm厚的金膜上，使我们能够克服上述限制。在TIR散射显微镜下对aunr进行成像，提供了良好的信噪比，并且不会导致图像恶化。在金衬底上，AuNR的激发偶极子与金衬底上的成像偶极子之间的强相互作用影响着AuNR的散射模式。甜甜圈形状的散射场分布允许在单帧内高通量确定聚焦aunr的三维空间方向，而不会出现角退化。因此，基于TIR散射的FOPI方法被证明是研究功能化纳米颗粒在各种功能表面上的动力学的杰出候选者。
The defocused orientation and position imaging (DOPI) and polarization-based in-focus imaging techniques have been widely used for detecting rotational motions with anisotropic gold nanorods (AuNRs) as orientation probes. However, these techniques have a number of significant limitations, such as the greatly reduced signal intensity and relatively low spatial and temporal resolutions for out-of-focus AuNRs and the angular degeneracy for in-focus AuNRs. Herein, we present a total internal reflection (TIR) scattering-based focused orientation and position imaging (FOPI) of AuNRs supported on a 50 nm thick gold film, which enables us to overcome the aforementioned limitations. Imaging AuNRs under the TIR scattering microscope provides excellent signal-to-noise ratio and results in no deteriorating images. The scattering patterns of AuNRs on the gold substrate are affected by the strong interaction of the excited dipole in the AuNR with the image dipole in the gold substrate. The doughnut-shaped scattering field distribution allows for high-throughput determination of the three-dimensional spatial orientation of infocus AuNRs within a single frame without angular degeneracy. Therefore, the TIR scattering-based FOPI method is demonstrated to be an outstanding candidate for studying dynamics of functionalized nanoparticles on a large variety of functional surfaces.