Homogeneous silver colloidal substrates optimal for metal-enhanced fluorescence

Lee, Daedu; Lee, Jaebeom; Song, Junghyun; Jen, Myungsam; Pang, Yoonsoo

doi:10.1039/c9cp00585d

Cited by 22 publications

(44 citation statements)

References 56 publications

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“…Steady-state absorption spectra were measured in a UV/Vis absorption spectrometer (Scinco S3100, Scinco, Seoul, Korea) and the emission spectra were measured in a home-built time-correlated single-photon counting (TCSPC) setup based on a TCSPC module (Picoharp 300, PicoQuant, Berlin, Germany) [64,65]. Fluorescence signals from the excitation of a picosecond diode laser (P-C-405, PicoQuant) at 405 nm were filtered by a long-pass filter (Omega Optical, Brattleboro, VT, USA) at 442 nm and collected by a photomultiplier tube detector (PMA 192, PicoQuant) attached to a monochromator (Cornerstone 260, Newport, Irvine, CA, USA).…”

Section: Steady-state Absorption and Emission Measurementsmentioning

confidence: 99%

Twisted Intramolecular Charge Transfer State of a “Push-Pull” Emitter

Lee

Jen

Pang

2020

IJMS

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The excited state Raman spectra of 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) in the locally-excited (LE) and the intramolecular charge transfer (ICT) states have been separately measured by time-resolved stimulated Raman spectroscopy. In a polar dimethylsulfoxide solution, the ultrafast ICT of DCM with a time constant of 1.0 ps was observed in addition to the vibrational relaxation in the ICT state of 4–7 ps. On the other hand, the energy of the ICT state of DCM becomes higher than that of the LE state in a less polar chloroform solution, where the initially-photoexcited ICT state with the LE state shows the ultrafast internal conversion to the LE state with a time constant of 300 fs. The excited-state Raman spectra of the LE and ICT state of DCM showed several major vibrational modes of DCM in the LE and ICT conformer states coexisting in the excited state. Comparing to the time-dependent density functional theory simulations and the experimental results of similar push-pull type molecules, a twisted geometry of the dimethylamino group is suggested for the structure of DCM in the S1/ICT state.

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Section: Steady-state Absorption and Emission Measurementsmentioning

confidence: 99%

Twisted Intramolecular Charge Transfer State of a “Push-Pull” Emitter

Lee

Jen

Pang

2020

IJMS

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“…Requirements for fiducial markers. The need for fiducialisation can be met through commercially available materials such as non-fluorescent gold nanoparticles 30,41 ; fluorescent gold nanoparticles 31,63 ; silver nanoparticles [64][65][66] ; fluorescent microsphere beads (TetraSpeck and PS-Speck) [67][68][69] ; quantum dots (QDs) 58,70,71 , fluorescent nanodiamonds 72 and magnetic Dynabeads 73,74 . Based on the data presented in this Protocol and factoring in the requirements of multimodal bioimaging, a fiducial is considered a candidate correlative tool in CLXT if: (a) it has fluorescence signal with high quantum yield (so it can be observed through excitation with visible light); (b) it absorbs X-rays in the 'water window' strongly (so that it can be easily identified); (c) it is of appropriate size (preferably between 100 -250 nm) so as to be clearly visible in both modalities, and (d) be well dispersed throughout the sample (to ensure it is present in all possible regions of interest).…”

Section: Experimental Designmentioning

confidence: 99%

“…2) A similar approach based on silver (Ag) nanoparticles as the inner core but surrounded by silicon oxide (SiO 2 ) shells incorporated with fluorophores (Ursa BioScience) [64][65][66] . These silver nanoparticles are referred to as metal-enhanced fluorescence (MEF) nanoparticles, where sustained, bright and photostable fluorescence is enhanced significantly by synchronised tuning of the metal core and silica shell optical properties [64][65][66] . We selected Rhodamine B as the fluorophore of the MEF and chose fiducials with particle diameters of 200 and 250 nm in total (core + shell).…”

Section: Selecting Commercial Fiducials For Direct Comparisonmentioning

confidence: 99%

Sample preparation strategies for efficient correlation of 3D SIM and soft X-ray tomography data at cryogenic temperatures

et al. 2021

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This protocol describes sample preparation strategies for correlative 3D cryo-SIM and cryo soft X-ray tomography. In addition, the authors provide a direct comparison and recommendations regarding the selection and use of fiducials for 3D correlation. TWEET A new protocol for sample preparation and fiducial selection for correlative cryo-SIM and cryo-soft X-ray tomography. #CLXT #cryoimaging #cellstructure #correlativeimaging COVER TEASER Correlative cryo-SIM and cryo-soft X-ray tomographyAbstract 3D correlative microscopy methods have revolutionised biomedical research allowing the acquisition of multi-dimensional information to gain an in-depth understanding of biological systems. With the advent of relevant cryo-preservation methods, correlative imaging of cryogenically preserved samples has led to nanometre resolution imaging (2-50 nm) under harsh imaging regimes such as electron and soft X-ray tomography. These methods have now been combined with conventional and super resolution fluorescence imaging at cryogenic temperatures to augment information content from a given sample resulting in the immediate requirement for protocols that facilitate hassle-free unambiguous cross correlation between microscopes. We present here sample preparation strategies and a direct comparison of different working fiducialisation regimes that facilitate 3D correlation of cryo-structured illumination microscopy and cryo-soft X-ray tomography. Our protocol has been tested at two synchrotron beamlines (B24 at Diamond Light Source in the UK and BL09 Mistral at ALBA in Spain) and has led to the development of a decision aid that facilitates experimental design with the strategic use of markers based on project requirements. This protocol takes between 1.5 hours and 3.5 days to complete, depending on the cell populations used (adherent cells may require several days to grow on sample carriers).

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“…It has been observed that each fabrication method exhibits significant MEF performance due to morphological-specific features. For example, metallic core-shell nanoparticles fabricated by chemical synthesis methods [97,100] have demonstrated enhancements beyond the MEF standard approach through controlling the cavity, which concentrates the electromagnetic field [13]. Similarly, the localization of the electromagnetic field increases with an increase in the length of nanostructures when fabricated with deposition methods [23,109].…”

Section: Summary and Future Outlookmentioning

confidence: 99%

Recent Developments in Plasmonic Nanostructures for Metal Enhanced Fluorescence-Based Biosensing

Koh²,

et al. 2020

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Metal-enhanced fluorescence (MEF) is a unique phenomenon of surface plasmons, where light interacts with the metallic nanostructures and produces electromagnetic fields to enhance the sensitivity of fluorescence-based detection. In particular, this enhancement in sensing capacity is of importance to many research areas, including medical diagnostics, forensic science, and biotechnology. The article covers the basic mechanism of MEF and recent developments in plasmonic nanostructures fabrication for efficient fluorescence signal enhancement that are critically reviewed. The implications of current fluorescence-based technologies for biosensors are summarized, which are in practice to detect different analytes relevant to food control, medical diagnostics, and forensic science. Furthermore, characteristics of existing fabrication methods have been compared on the basis of their resolution, design flexibility, and throughput. The future projections emphasize exploring the potential of non-conventional materials and hybrid fabrication techniques to further enhance the sensitivity of MEF-based biosensors.

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Homogeneous silver colloidal substrates optimal for metal-enhanced fluorescence

Abstract: Particle-size-dependent fluorescence enhancements and dynamics on homogeneous silver nanosurfaces show a strong dependence on the spectral properties of surface plasmons.

Cited by 22 publications

References 56 publications

Twisted Intramolecular Charge Transfer State of a “Push-Pull” Emitter

Twisted Intramolecular Charge Transfer State of a “Push-Pull” Emitter

Sample preparation strategies for efficient correlation of 3D SIM and soft X-ray tomography data at cryogenic temperatures

Recent Developments in Plasmonic Nanostructures for Metal Enhanced Fluorescence-Based Biosensing

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