Combining our knowledge on plasmonic gold nanorods and the TIR illumination scheme, we have demonstrated a dual-color total internal reflection scattering (TIRS) microscopy imaging system that can dynamically track 3D orientation changes of multiple gold nanorods. The p-polarized excitation light (perpendicular to the horizontal plane) at the longitudinal LSPR wavelength is used for tracking the out-of-plane angle, while the s-polarized excitation light (parallel to the horizontal surface) at the transverse LSPR wavelength is used for tracking the in-plane angle. This technique is capable of resolving the out-of-plane angle with a high angular resolution comparable to that for the in-plane angle to probe rotational dynamics of gold nanorods interacting with functional surfaces. In combination with superlocalization through point spread function (PSF) fitting, we have resolved the conformations of surface-bound nanorods in unprecedented detail. Furthermore, we have developed another TIRS-based method based on the far-field scattering patterns of in-focus gold nanorods supported on a dielectric gold film. The 3D orientation of AuNRs within a single frame can be extracted from the characteristic image patterns. These TIRS microscopy techniques open up new opportunities for studying important phenomena at solid/liquid interfaces.

Single particle rotational tracking at solid-liquid interfaces

248th National Meeting (2014)

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