Three-Dimensional Orientation of Anisotropic Plasmonic Aggregates at Intracellular Nuclear Indentation Sites by Integrated Light Sheet Super-Resolution Microscopy

Three-dimensional
(3D) orientations of individual anisotropic plasmonic
nanoparticles in aggregates were observed in real time by integrated
light sheet super-resolution microscopy (iLSRM).
Asymmetric light scattering of a gold nanorod (AuNR) was used to trigger
signals based on the polarizer angle. Controlled photoswitching was
achieved by turning the polarizer and obtaining a series of images
at different polarization directions. 3D subdiffraction-limited super-resolution
images were obtained by superlocalization of scattering signals as
a function of the anisotropic optical properties of AuNRs. Varying
the polarizer angle allowed resolution of the orientation of individual
AuNRs. 3D images of individual nanoparticles were resolved in aggregated
regions, resulting in as low as 64 nm axial resolution and 28 nm spatial
resolution. The proposed imaging setup and localization approach demonstrates
a convenient method for imaging under a noisy environment where the
majority of scattering noise comes from cellular components. This
integrated 3D iLSRM and localization technique was
shown to be reliable and useful in the field of 3D nonfluorescence
super-resolution imaging.