Challenges investigating molecules on plasmonic nanostructures have limited understanding of these interactions. However, the chemically specific information in the surface-enhanced Raman scattering (SERS) spectrum can identify perturbations in the adsorbed molecules to provide insight relevant to applications in sensing, catalysis, and energy conversion. Here, we demonstrate spectrally resolved SERS imaging, to simultaneously image and collect the SERS spectra from molecules adsorbed on individual nanoparticles. We observe intensity and frequency fluctuations in the SERS signal on the time scale of tens of milliseconds from -mercaptobenzoic acid (MBA) adsorbed to gold nanoparticles. The SERS signal fluctuations correlate with density functional theory calculations of radicals generated by the interaction between MBA and plasmon-generated hot electrons. Applying localization microscopy to the data provides a super-resolution spectrally resolved map that indicates the plasmonic-induced molecular charging occurs on the extremities of the nanoparticles, where the localized electromagnetic field is reported to be most intense.
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http://dx.doi.org/10.1021/acsnanoscienceau.1c00031 | DOI Listing |
Cureus
December 2024
Department of Ophthalmology, Unidade Local de Saúde de São João, Porto, PRT.
Migraine, a neurological disorder often accompanied by symptoms such as visual disturbances, nausea, and photophobia, involves complex interactions between genetic and environmental factors, while vascular factors are also implicated, influenced by both genetic predisposition and environmental triggers. This case report discusses a 41-year-old male with a history of migraine with visual aura, presenting with sudden left-eye visual loss. Comprehensive ophthalmologic examination revealed a central scotoma, while multimodal imaging, including spectral-domain optical coherence tomography (SD-OCT), showed focal alterations in the outer plexiform layer.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
The William H. Annesley, Jr, EyeBrain Center, Farber Neuroscience Institute at Thomas Jefferson University, Philadelphia, PA, USA.
Background: FLIO a novel in vivo reproducible, non-invasive imaging technology, measures fluorescence lifetime decay in two spectral channels for short-lived retinal chromophores in two domains: Channel 1 emission wavelength 498-560 nm corresponding to NADH and FAD/ATP function and Channel 2, 560-720 nm wavelength corresponding to lipofuscin/lysosomal function. These data reflect the retinal mitochondrial molecular environment. Mitochondrial dysfunction has been recently explored as a cause of decreased synaptic function and cognitive decline in AD.
View Article and Find Full Text PDFLuminescence
January 2025
Vlokh Institute of Physical Optics, Ivan Franko National University of Lviv, Lviv, Ukraine.
Spectroscopic properties of Tb-doped and Tb-Ag codoped lithium tetraborate (LTB) glasses with LiBO (or LiO-2BO) composition are investigated and analysed using electron paramagnetic resonance (EPR), optical absorption, photoluminescence (PL) and photoluminescence excitation (PLE) spectra, PL decay kinetics and absolute quantum yield (QY) measurements. PL spectra of the investigated glasses show numerous narrow emission bands corresponding to the D → F (J = 6-0) and D → F (J = 5-3) transitions of Tb (4f) ions. The most intense PL band of Tb ions at 541 nm (D → F transition) is characterised by a lifetime slightly exceeding 2.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Huygens-Kamerlingh Onnes Laboratory, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands.
Fluorescence spectra of single terrylene molecules adsorbed on hexagonal boron nitride flakes were recorded at cryogenic temperatures. The pure electronic transitions of terrylene molecules are spread over a broad energy scale from 570 to 610 nm. Surprisingly, peaks in the vibrationally resolved fluorescence spectrum show intensity variations of ≤20-fold between molecules.
View Article and Find Full Text PDFCarbohydr Polym
March 2025
Department of Molecular Sciences, Swedish University of Agricultural Sciences, Almas Allé 5, Uppsala 75651, Sweden. Electronic address:
Chitin is the second most abundant biopolymer in nature after cellulose and is composed of N-acetylglucosamine (GlcNAc) connected via β(1 → 4)-glycosidic bonds. Despite its prominence in nature and diverse roles in pharmaceutical and food technological applications, there is still a need to develop methods to study structure and function of chitin and its corresponding oligomers. Efforts have been made to analyse chitin oligomers by NMR spectroscopy, but spectral overlap has prevented any differentiation between the interior residues.
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