Effects of Tuning Fluorophore Density, Identity, and Spacing on Reconstructed Images in Super-Resolution Imaging of Fluorophore-Labeled Gold Nanorods

A triplet-state mediated super-resolution imaging technique is used to optically investigate the locations of single fluorescently labeled double-stranded DNA (dsDNA) ligands bound to gold nanorods (AuNRs). Previous work on this system has shown significant apparent heterogeneity in dsDNA ligand binding across the AuNR surface, but the reconstructed images have yielded dimensions that are smaller than the underlying AuNR substrate. Here, we tune the fluorophore density and identity to determine if the properties of the fluorophore impact the reconstructed images. While lowering the fluorophore density on the AuNR surface reduces the probability of simultaneous emission events and fluorophore self-quenching, we do not observe an improvement in the reconstructed image size and ultimately suffer from under-sampling of the surface. As alternative strategies, the identity of the fluorescent label, and thus the photophysics of the system, was also changed and again, the size of the reconstructed images remained...