Orientational Imaging of a Single Gold Nanorod at the Liquid/Solid Interface with Polarized Evanescent Field Illumination

Understanding the mechanistic information on many kinetic processes requires the exploration of dynamic rotational information on the target object at the single particle (or molecule) level. In this work, we developed a new strategy, total internal reflection scattering (TIRS) microscopy, to determine the full three-dimensional (3D) angular information on a single gold nanorod (GNR) close to the liquid/solid interface. It was found that the 3D orientational information on individual GNR could be readily elucidated by using p-polarized TIRS illumination through deciphering the orientation-coded intensity distribution pattern in a single TIRS image. In comparison with the previously reported strategies, this method does not require complicated focal plane correction, affording a versatile pathway to track the rotational dynamics close to the interface in a high throughput manner. The methodology presented here, therefore, demonstrates a promising approach that can be applied to fluidic membranes, including membranes with polymers, bound proteins, and so on.