Imaging Nanostructures by Single-Molecule Localization Microscopy in Organic Solvents

Abstract

The introduction of super-resolution fluorescence microscopy (SRM) opened an unprecedented vista into nanoscopic length scales, unveiling a new degree of complexity in biological systems in aqueous environments. Regrettably, supramolecular chemistry and material science benefited far less from these recent developments. Here we expand the scope of SRM to photoactivated localization microscopy (PALM) imaging of synthetic nanostructures that are highly dynamic in organic solvents. Furthermore, we characterize the photophysical properties of commonly used photoactivatable dyes in a wide range of solvents, which is made possible by the addition of a tiny amount of an alcohol. As proof-of-principle, we use PALM to image silica beads with radii close to Abbe's diffraction limit. Individual nanoparticles are readily identified and reliably sized in multicolor mixtures of large and small beads. We further use SRM to visualize nm-thin yet μm-long dynamic, supramolecular polymers, which are among the most challenging molecular systems to image.

Super‐resolution Fluorescence Imaging for Materials Science

“…Belov and co‐workers introduced caged rhodamines NN, which, after irradiation with UV‐light, form rhodamine derivatives. These dyes have been shown to be suitable for super‐resolution microscopy in different organic solvents when a small amount of a nucleophilic solvent such as an alcohol is added . STAR and CAGE dyes have also allowed the imaging of polymeric micelles in organic solvents by both STED and SMLM .…”

Inhibition of cancer cell migration with CuS@mSiO₂-PEG nanoparticles by repressing MMP-2/MMP-9 expression

“…Eight male BALB/c nude mice were subcutaneously injected with 5×10 6 HeLa cells on both sides of the back. The cells injected in the left side were pre-stimulated with 80 μg/mL NPs for 24 h before digestion.…”

“…32 Briefly, a single cell suspension of HeLa cells was prepared for tail vein injection. Mice were intravenously injected in the tail vein using insulin syringes with 1×10 6 tumor cells in 100 μL of PBS. Before injection, based on the uptake and degradation of NPs absorbed, 33,34 the cells in the experimental group were pre-stimulated with 80 μg/mL NPs for 24 h to ensure sufficient absorption.…”

“…1 Briefly, the functions of nanomedicine include site-directed drug delivery, 2 imaging or tracing, 3 and even immunomodulation. 4 Moreover, the potential of multifunctional theranostic systems is similar to that of photothermal therapy (PTT) 5 or optical imaging applications 6 in addition to that of the direct influence of the NPs. 7 Besides, interference techniques, such as PTT and drug delivery systems, have been widely used.…”

Fluorescent Diarylethene Photoswitches—A Universal Tool for Super‐Resolution Microscopy in Nanostructured Materials

“…The visualization, with the above described methods, of apolar structures found in material science is often impossible since the employed polar switching buffers cannot significantly access apolar structures, whereas fluorescent proteins, if appropriate to be used, would denature under such conditions. As a consequence, super‐resolution microscopy has so far not been used extensively to address topics in soft matter or polymer science …”