Superlocalization microscopy enables the position of single plasmonic nanoparticles to be determined with <25 nm precision, enabling single-nanoparticle tracking and super-resolution imaging experiments to be conducted with sub-diffraction-limited spatial resolution. In many of these applications, the superlocalized position of the nanoparticle is assumed to correspond to the geometric center of the nanoparticle. However, work reported by Wang and co-workers in this issue of ACS Nano suggests that this assumption can be incorrect, based on studies in which electrochemically charging a nanoparticle leads to reproducible shifts in its scattering center. The shift is believed to originate from nonuniform charge accumulation in the nanoparticle, due to the inherent heterogeneity in nanoparticle surface properties. This Perspective explores the implications of this result, both for using this shift to probe dynamic changes in nanoparticle surface chemistry as well as for exploiting nonuniform charge accumulation to promote site-specific chemical reactions.
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http://dx.doi.org/10.1021/acsnano.9b04062 | DOI Listing |
ACS Nano
October 2024
Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States.
Super-resolution surface-enhanced Raman scattering (SERS) allows researchers to overcome the resolution limit of far field optical microscopy and peer into electromagnetic hot spots with nanoscale resolution. By localizing the signal from single (or few) molecules on the surface of plasmonic nanoparticle aggregates, relationships between the spatial origin of the SERS signal, local electromagnetic field enhancements, and SERS intensity can be determined. This Perspective describes the successes and challenges of super-resolution SERS, from the earliest mapping of single-molecule SERS hot spots to the current state-of-the-art, while highlighting open questions and future opportunities to advance the field.
View Article and Find Full Text PDFNano Lett
March 2024
Laboratoire de physique de l'ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 75005 Paris, France.
We report on the photoluminescence of pairs of organic color centers in single-wall carbon nanotubes grafted with 3,5-dichlorobenzene. Using various techniques such as intensity correlations, superlocalization microscopy, and luminescence excitation spectroscopy, we distinguish two pairs of color centers grafted on the same nanotube; the distance between the pairs is on the order of several hundreds of nanometers. In contrast, by studying the strong temporal correlations in the spectral diffusion in the framework of the photoinduced Stark effect, we can estimate the distance within each pair to be on the order of a few nanometers.
View Article and Find Full Text PDFPerfusion by the microcirculation is key to the development, maintenance and pathology of tissue. Its measurement with high spatiotemporal resolution is consequently valuable but remains a challenge in deep tissue. Ultrasound Localization Microscopy (ULM) provides very high spatiotemporal resolution but the use of microbubbles requires low contrast agent concentrations, a long acquisition time, and gives little control over the spatial and temporal distribution of the microbubbles.
View Article and Find Full Text PDFNano Lett
September 2022
Université de Bordeaux, Institut d'Optique & Centre National de la Recherche Scientifique, UMR 5298, 33400 Talence, France.
We provide evidence of a local synaptic nanoenvironment in the brain extracellular space (ECS) lying within 500 nm of postsynaptic densities. To reveal this brain compartment, we developed a correlative imaging approach dedicated to thick brain tissue based on single-particle tracking of individual fluorescent single wall carbon nanotubes (SWCNTs) in living samples and on speckle-based HiLo microscopy of synaptic labels. We show that the extracellular space around synapses bears specific properties in terms of morphology at the nanoscale and inner diffusivity.
View Article and Find Full Text PDFACS Nano
February 2021
State Key Laboratory of Analytical Chemistry for Life Science, Chemistry and Biomedicine Innovation Center, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Determining the trajectory of ionic transport and diffusion within single electroactive nanomaterials is critical for understanding the charging kinetics and capacity fading associated with ion batteries, with implications for rational design of excellent-performance electrode materials. While the horizontal pathway of mass transport has been feasibly investigated by optical superlocalization methods and electron microscopes, determination on the vertical trajectory has proven a more challenging task. Herein, we developed dual-angle total internal reflection microscopy by simultaneously introducing different angle-dependent illumination depths to trace the optical centroid shifts of nano-objects in the vertical dimension.
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