scholarly journals Enhancement of Raman light scattering in dye-labeled cell membrane on metal-containing conducting polymer film

2016 ◽  
Vol 30 (13) ◽  
pp. 1642018 ◽  
Author(s):  
H. V. Grushevskaya ◽  
N. G. Krylova ◽  
I. V. Lipnevich ◽  
T. I. Orekhovskaja ◽  
V. P. Egorova ◽  
...  
Keyword(s):  
Plasmon Resonance ◽  
Organometallic Complexes ◽  
Vibrational Modes ◽  
Membrane Structures ◽  
Cell Monolayers ◽  
Nanoporous Anodic Alumina ◽  
Lb Film ◽  
Subcellular Membrane ◽  
Raman Light Scattering ◽  
Alumina Supports

An enhanced Raman spectroscopy method based on a plasmon resonance in ultrathin metal-containing LB-film deposited on nanoporous anodic alumina supports has been proposed. This material has been utilized to enhance Raman scattering of light in fluorescent-labeled subcellular membrane structures. It has been shown that the plasmon resonance between vibrational modes of the organometallic complexes monolayers and dye-labeled subcellular structures happens. It makes possible to detect interactions between living cell monolayers and an extracellular matrix.

scholarly journals Integrating surface plasmon resonance and slow photon effects in nanoporous anodic alumina photonic crystals for photocatalysis

2019 ◽  
Vol 9 (12) ◽  
pp. 3158-3176 ◽  
Author(s):  
Siew Yee Lim ◽  
Cheryl Suwen Law ◽  
Lina Liu ◽  
Marijana Markovic ◽  
Andrew D. Abell ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Photonic Crystals ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Anodic Alumina ◽  
Bragg Reflectors ◽  
Distributed Bragg Reflectors ◽  
Nanoporous Anodic Alumina ◽  
Photocatalytic Reactions

This study explores the potential of gold-coated titania-functionalized nanoporous anodic alumina distributed Bragg reflectors (Au-TiO2-NAA-DBRs) as platforms to enhance photocatalytic reactions by integrating “slow photons” and surface plasmon resonance (SPR).

scholarly journals Non-Radiative Processes and Vibrational Pumping in Surface-Enhanced Raman Scattering

2021 ◽  
Author(s):  
◽  
Christopher Galloway
Keyword(s):  
Cross Section ◽  
Single Molecule ◽  
Cross Sections ◽  
Plasmon Resonance ◽  
Additional Contribution ◽  
Vibrational Modes ◽  
Silver Colloids ◽  
Surface Enhanced ◽  
Vibrational Population ◽  
Anti Stokes

<p><b>The main focus of this thesis was the physical interpretation of the pumping cross-section. This was achieved by performing a statistical analysis of single molecule vibrational pumping events in which both the SERS and pumping cross-sections could be measured simultaneously. Samples were constructed in which small aggregates of silver colloids were evenly distributed on a dry surface.</b></p> <p>The sample was then cooled to 77K so that the main mechanism for creating a vibrational population was through Stokes scattering. Spatial mappings were then performed which measured how the SERS spectrum varied with positionon the sample and the single molecule events were identified. The SERS cross-sections were determined from the Stokes intensity while the pumping cross-sections were determined from the ratio of the anti-Stokes and Stokes peaks. It was observed that the pumping cross-section was often significantly larger than the SERS cross-section, as much as four orders of magnitude in some cases. Several attempts were made to explain this discrepancy including the possibility ofthe surface plasmon resonance favouring anti-Stokes scattering, underestimated lifetimes for the vibrational modes, and additional pumping from fluorescence. However, the most likely candidate was non-radiative Stokes scattering by the observed molecule which would increase the vibrational population but would not increase the Stokes intensity. To estimate the proportion of scattered light that is radiative or non-radiative,single molecule measurements were performed under both surface-enhanced and unmodified conditions. By comparing the fluorescence and Raman intensities under these scenarios, it was possible to estimate the radiative and non-radiative enhancement factors. It was found that the non-radiative SERS cross-section was typically much larger than the radiative cross-section for samples consisting of aggregated silver colloids. The discrepancy between the pumping and SERS cross-section (which is the radiative cross-section) could therefore be explained by non-radiative scattering dominating the creation of the vibrational population, along with an additional contribution due to the plasmon resonance favouring certain vibrational modes. Furthermore, the lifetime of a molecule after it has been excited to the first electronic state was estimated to be as short as 25 fs. It would be impossible to measure lifetimes of this order of magnitude in single molecules using time-resolved techniques. Furthermore, to the very best of our knowledge, this is the first time that an experimental determination of the non-radiative SERS cross-section has been made.</p>

scholarly journals Non-Radiative Processes and Vibrational Pumping in Surface-Enhanced Raman Scattering

2021 ◽  
Author(s):  
◽  
Christopher Galloway
Keyword(s):  
Cross Section ◽  
Single Molecule ◽  
Cross Sections ◽  
Plasmon Resonance ◽  
Additional Contribution ◽  
Vibrational Modes ◽  
Silver Colloids ◽  
Surface Enhanced ◽  
Vibrational Population ◽  
Anti Stokes

<p><b>The main focus of this thesis was the physical interpretation of the pumping cross-section. This was achieved by performing a statistical analysis of single molecule vibrational pumping events in which both the SERS and pumping cross-sections could be measured simultaneously. Samples were constructed in which small aggregates of silver colloids were evenly distributed on a dry surface.</b></p> <p>The sample was then cooled to 77K so that the main mechanism for creating a vibrational population was through Stokes scattering. Spatial mappings were then performed which measured how the SERS spectrum varied with positionon the sample and the single molecule events were identified. The SERS cross-sections were determined from the Stokes intensity while the pumping cross-sections were determined from the ratio of the anti-Stokes and Stokes peaks. It was observed that the pumping cross-section was often significantly larger than the SERS cross-section, as much as four orders of magnitude in some cases. Several attempts were made to explain this discrepancy including the possibility ofthe surface plasmon resonance favouring anti-Stokes scattering, underestimated lifetimes for the vibrational modes, and additional pumping from fluorescence. However, the most likely candidate was non-radiative Stokes scattering by the observed molecule which would increase the vibrational population but would not increase the Stokes intensity. To estimate the proportion of scattered light that is radiative or non-radiative,single molecule measurements were performed under both surface-enhanced and unmodified conditions. By comparing the fluorescence and Raman intensities under these scenarios, it was possible to estimate the radiative and non-radiative enhancement factors. It was found that the non-radiative SERS cross-section was typically much larger than the radiative cross-section for samples consisting of aggregated silver colloids. The discrepancy between the pumping and SERS cross-section (which is the radiative cross-section) could therefore be explained by non-radiative scattering dominating the creation of the vibrational population, along with an additional contribution due to the plasmon resonance favouring certain vibrational modes. Furthermore, the lifetime of a molecule after it has been excited to the first electronic state was estimated to be as short as 25 fs. It would be impossible to measure lifetimes of this order of magnitude in single molecules using time-resolved techniques. Furthermore, to the very best of our knowledge, this is the first time that an experimental determination of the non-radiative SERS cross-section has been made.</p>

The Role of Junctophilin Proteins in Cellular Function

2022 ◽  
Author(s):  
Stephan E. Lehnart ◽  
Xander H.T. Wehrens
Keyword(s):  
Neuronal Cell ◽  
Cell Types ◽  
Evolutionary Analysis ◽  
Membrane Structures ◽  
Comprehensive Overview ◽  
Functional Roles ◽  
Protein Levels ◽  
Subcellular Membrane ◽  
Membrane Tethering ◽  
Carboxy Terminal

Junctophilins (JPHs) comprise a family of structural proteins that connect the plasma membrane to intracellular organelles such as the endo/sarcoplasmic reticulum. Tethering of these membrane structures results in the formation of highly organized subcellular junctions that play important signaling roles in all excitable cell types. There are four JPH isoforms, expressed primarily in muscle and neuronal cell types. Each JPH protein consists of 6 'membrane occupation and recognition nexus' (MORN) motifs, a joining region connecting these to another set of 2 MORN motifs, a putative alpha-helical region, a divergent region exhibiting low homology between JPH isoforms, and a carboxy-terminal transmembrane region anchoring into the ER/SR membrane. JPH isoforms play essential roles in developing and maintaining subcellular membrane junctions. Conversely, inherited mutations in JPH2 cause hypertrophic or dilated cardiomyopathy, while trinucleotide expansions in the JPH3 gene cause Huntington Disease-Like 2. Loss of JPH1 protein levels can cause skeletal myopathy, while loss of cardiac JPH2 levels causes heart failure and atrial fibrillation, among other disease. This review will provide a comprehensive overview of the JPH gene family, phylogeny, and evolutionary analysis of JPH genes and other MORN domain proteins. JPH biogenesis, membrane tethering, and binding partners will be discussed, as well as functional roles of JPH isoforms in excitable cells. Finally, potential roles of JPH isoform deficits in human disease pathogenesis will be reviewed.

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