Dataset Information

Chemical Control and Spectral Fingerprints of Electronic Coupling in Carbon Nanostructures.

ABSTRACT: The optical and electronic properties of atomically thin materials such as single-walled carbon nanotubes and graphene are sensitively influenced by substrates, the degree of aggregation, and the chemical environment. However, it has been experimentally challenging to determine the origin and quantify these effects. Here we use time-dependent density-functional-theory calculations to simulate these properties for well-defined molecular systems. We investigate a series of core-shell structures containing C60 enclosed in progressively larger carbon shells and their perhydrogenated or perfluorinated derivatives. Our calculations reveal strong electronic coupling effects that depend sensitively on the interparticle distance and on the surface chemistry. In many of these systems we predict considerable orbital mixing and charge transfer between the C60 core and the enclosing shell. We predict that chemical functionalization of the shell can modulate the electronic coupling to the point where the core and shell are completely decoupled into two electronically independent chemical systems. Additionally, we predict that the C60 core will oscillate within the confining shell, at a frequency directly related to the strength of the electronic coupling. This low-frequency motion should be experimentally detectable in the IR region.

SUBMITTER: Klos J

PROVIDER: S-EPMC5555747 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Chemical Control and Spectral Fingerprints of Electronic Coupling in Carbon Nanostructures.

Kłos Jacek J Kim Mijin M Alexander Millard H MH Wang YuHuang Y

The journal of physical chemistry. C, Nanomaterials and interfaces 20161207 51

The optical and electronic properties of atomically thin materials such as single-walled carbon nanotubes and graphene are sensitively influenced by substrates, the degree of aggregation, and the chemical environment. However, it has been experimentally challenging to determine the origin and quantify these effects. Here we use time-dependent density-functional-theory calculations to simulate these properties for well-defined molecular systems. We investigate a series of core-shell structures co ...[more]

PMID: 28819465

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Project description:Traumatic brain injury (TBI) affects millions of people of all ages around the globe. TBI is notoriously hard to diagnose at the point of care, resulting in incorrect patient management, avoidable death and disability, long-term neurodegenerative complications, and increased costs. It is vital to develop timely, alternative diagnostics for TBI to assist triage and clinical decision-making, complementary to current techniques such as neuroimaging and cognitive assessment. These could deliver rapid, quantitative TBI detection, by obtaining information on biochemical changes from patient's biofluids. If available, this would reduce mis-triage, save healthcare providers costs (both over- and under-triage are expensive) and improve outcomes by guiding early management. Herein, we utilize Raman spectroscopy-based detection to profile a panel of 18 raw (human, animal, and synthetically derived) TBI-indicative biomarkers (N-acetyl-aspartic acid (NAA), Ganglioside, Glutathione (GSH), Neuron Specific Enolase (NSE), Glial Fibrillary Acidic Protein (GFAP), Ubiquitin C-terminal Hydrolase L1 (UCHL1), Cholesterol, D-Serine, Sphingomyelin, Sulfatides, Cardiolipin, Interleukin-6 (IL-6), S100B, Galactocerebroside, Beta-D-(+)-Glucose, Myo-Inositol, Interleukin-18 (IL-18), Neurofilament Light Chain (NFL)) and their aqueous solution. The subsequently derived unique spectral reference library, exploiting four excitation lasers of 514, 633, 785, and 830 nm, will aid the development of rapid, non-destructive, and label-free spectroscopy-based neuro-diagnostic technologies. These biomolecules, released during cellular damage, provide additional means of diagnosing TBI and assessing the severity of injury. The spectroscopic temporal profiles of the studied biofluid neuro-markers are classed according to their acute, sub-acute, and chronic temporal injury phases and we have further generated detailed peak assignment tables for each brain-specific biomolecule within each injury phase. The intensity ratios of significant peaks, yielding the combined unique spectroscopic barcode for each brain-injury marker, are compared to assess variance between lasers, with the smallest variance found for UCHL1 (σ2 = 0.000164) and the highest for sulfatide (σ2 = 0.158). Overall, this work paves the way for defining and setting the most appropriate diagnostic time window for detection following brain injury. Further rapid and specific detection of these biomarkers, from easily accessible biofluids, would not only enable the triage of TBI, predict outcomes, indicate the progress of recovery, and save healthcare providers costs, but also cement the potential of Raman-based spectroscopy as a powerful tool for neurodiagnostics.

Dataset Information

Chemical Control and Spectral Fingerprints of Electronic Coupling in Carbon Nanostructures.

Publications

Chemical Control and Spectral Fingerprints of Electronic Coupling in Carbon Nanostructures.

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