Focused Orientation and Position Imaging (FOPI) of Single Anisotropic Plasmonic Nanoparticles by Total Internal Reflection Scattering Microscopy

TitleFocused Orientation and Position Imaging (FOPI) of Single Anisotropic Plasmonic Nanoparticles by Total Internal Reflection Scattering Microscopy
Publication TypeJournal Article
Year of Publication2012
AuthorsHa JW, Marchuk K, Fang N
Journal TitleNano Letters
Volume12
Pages4282-4288
Date Published08
Type of ArticleArticle
ISBN Number1530-6984
Accession NumberWOS:000307211000065
KeywordsABSORPTION, dielectric-constant, Focused orientation imaging, gold film, gold nanorod, gold nanorods, matter, microscopy, MOLECULE, polarization, rotational-dynamics, sensors, single-particle tracking, surfaces, total internal reflection scattering, TRACKING
Abstract

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.

URL<Go to ISI>://WOS:000307211000065
DOI10.1021/nl301972t
Alternate JournalNano Lett.