Plasmonic Nanoprobes for Multiplexed Fluorescence‐Free Super‐Resolution Imaging

Abstract

Noble metal nanoparticles (NPs), owing to their unique optical and physicochemical properties, are routinely used for optical imaging and labeling of biological specimens. Even though they can provide vital information for studying multiple cellular events and their interplays at the same time, optically multiplexing and resolving specific NPs within a diffraction‐limited region labeled in complex biological specimens remains a fundamental challenge. By introducing and manipulating plasmonic resonance assisted saturable scattering effects, multiplexed fluorescence‐free super‐resolution imaging of gold NPs in tumor cells with remarkable subdiffraction resolution is demonstrated. The saturable scattering allows fluorescence‐free resolving single plasmonic nanoprobes with significantly improved resolution down to ≈100 nm. The revealed plasmonic resonance assisted saturation effect as well as the associated spectral flexibility to variant sizes provides access to multiplexing capability in complex bioenvironments. The demonstrated feasibility of two‐color super‐resolution cellular imaging is achieved at ultralow suppression powers ≈0.28 MW cm−2, corresponding to a two‐order of magnitude improvement compared to the state‐of‐the‐art of stimulated emission depletion (STED) nanoscopy.

Anapole mediated giant photothermal nonlinearity in nanostructured silicon

“…1b, the scattering intensity displays a strong nonlinear response with increasing excitation radiances. Such nonlinearity can be analyzed by examining the PSFs of scattering signals at the focus of the microscope 33,[36][37][38][39] . Fig.…”

“…We examine the photothermal nonlinearity through analyzing the scattering PSFs of single nanodisks 30,[34][35][36][37] . Figure 2d, e depicts the evolution of the PSFs from isolated Si nanodisks by increasing excitation intensities.…”

“…13). In analogy to gold nanoparticles 35,37 , the applicability of such Si nanostructures as fluorescence-free labeling contrasts in photothermal nonlinearity assisted cellular imaging might be feasible combining their biodegradable features.…”

“…The derived gradual temperature increase under photothermal effect shows a nice agreement with the results from Raman Microscope system: The nonlinear scattering measurements were performed based on Abberior 775 STED confocal microscope (Abberior Instruments GmbH, Göttingen). We coupled continuous-wave laser line (532nm) into the system for CW illumination 37,39 . The excitation beam was first spatially filtered and then focused onto the sample.…”

Shedding New Lights Into STED Microscopy: Emerging Nanoprobes for Imaging

“…Resultantly, dark spot in a circle of dim light occurs, indicating the location of nanoparticles (Chen et al, 2018). Furthermore, the idea of STED-like microscopy can be broadened beyond fluorescence imaging, such as the suppression of scattering imaging (SUSI) method with plasmonic gold nanoparticles (Xu et al, 2018).…”