Switching on the Fluorescence Emission of Polypyridine Ligands by Simultaneous Zinc(II) Binding and Protonation

ChemPlusChem ◽  
2020 ◽  
Vol 85 (4) ◽  
pp. 659-671
Author(s):  
Luca Conti ◽  
Claudia Giorgi ◽  
Barbara Valtancoli ◽  
Paola Paoli ◽  
Patrizia Rossi ◽  
...  
Keyword(s):  
Fluorescence Emission ◽  
Polypyridine Ligands

Enhanced-Fluorescence of a Dye on DNA- assembled Gold Nano-Dimers Discriminated by Lifetime Correlation Spectroscopy

2017 ◽  
Author(s):  
Pedro M. R. Paulo ◽  
David Botequim ◽  
Agnieszka Jóskowiak ◽  
Sofia Martins ◽  
Duarte M. F. Prazeres ◽  
...  
Keyword(s):  
Single Molecule ◽  
Fluorescence Emission ◽  
Directed Assembly ◽  
Plasmon Mode ◽  
Correlation Spectroscopy ◽  
Enhanced Fluorescence ◽  
Detection Volume ◽  
Relaxation Component ◽  
Good Agreement ◽  
Confocal Detection

<div> <div> <div> <p>We have employed DNA-directed assembly to prepare dimers of gold nanoparticles and used their longitudinally coupled plasmon mode to enhance the fluorescence emission of an organic red-emitting dye, Atto-655. The plasmon- enhanced fluorescence of this dye using dimers of 80 nm particles was measured at single molecule detection level. The top enhancement factors were above 1000-fold in 71% of the dimers within a total of 32 dimers measured, and, in some cases, they reached almost 4000-fold, in good agreement with model simulations. Additionally, fluorescence lifetime correlation analysis enabled the separation of enhanced from non-enhanced emission simultaneously collected in our confocal detection volume. This approach allowed us to recover a short relaxation component exclusive to enhanced emission that is attributed to the interaction of the dye with DNA in the interparticle gaps. </p> </div> </div> </div>

The Difference in Sensing Properties Towards Anions between Two Pyridinium Amide-Based Receptors with a Subtle Change of H-Bond Position

2020 ◽  
Vol 17 (6) ◽  
pp. 472-478
Author(s):  
Wei-tao Gong ◽  
Wei-dong Qu ◽  
Guiling Ning
Keyword(s):  
Fluorescence Enhancement ◽  
Small Difference ◽  
Fluorescence Emission ◽  
Subtle Change ◽  
Sensing Properties ◽  
Naked Eye ◽  
Recognition Ability ◽  
The Difference ◽  
L1 And L2

Two pyridinium amide-based receptors L1 and L2 with a small difference of H-bond position of the amide have been synthesized and characterized. Interestingly, they exhibited a huge difference in sensing towards AcO- and H2PO4 -, respectively. Receptor L1 was found to be ‘naked-eye’ selective for AcO- anions, while receptor L2 showed clear fluorescence enhancement selective to H2PO4 - anion. The recognition ability has been established by fluorescence emission, UV-vis spectra, and 1HNMR titration.

Isolierung von PS II-Partikeln mit in vivo Eigenschaften aus Euglena gracilis, Stamm Z / Isolation of PS II-Particels with in vivo Characteristics from Euglena gracilis, Stamm Z

1982 ◽  
Vol 37 (3-4) ◽  
pp. 256-259 ◽  
Author(s):  
F. Schuler ◽  
P. Brandt ◽  
W. Wießner
Keyword(s):  
Euglena Gracilis ◽  
Fluorescence Emission ◽  
Improved Method ◽  
Ps Ii ◽  
Ps I ◽  
Emission And Absorption Spectra ◽  
Chlorophyll Protein ◽  
Ps Ii Activity ◽  
Photosystem Ii Particles

Abstract An improved method for isolation of (photosystem II)-particles from Euglena gracilis, strain Z was established. PS II-particles isolated by ultrasonic treatment and following differential centrifugation show fluorescence emission and absorption spectra identical with in vivo properties of Euglena gracilis. These PS II-particles have only PS II-activity and contain CP a, the typical chlorophyll-protein-complex of PS II. No contamination of PS I-components are detectable.

Quantitative Measurement of Fluorescent Layers with Respect to Spatial Thickness Variations and Substrate Properties

2020 ◽  
Vol 74 (4) ◽  
pp. 439-451
Author(s):  
Philipp Holz ◽  
Christoph Pönisch ◽  
Albrecht Brandenburg
Keyword(s):  
Manufacturing Industry ◽  
Quantitative Measurement ◽  
Fluorescence Emission ◽  
Fluorescence Analysis ◽  
Thin Layers ◽  
Fluorescence Signal ◽  
Functional Coatings ◽  
Custom Made ◽  
Substrate Properties ◽  
Thickness Variations

Imaging fluorescence spectroscopy proves to be a fast and sensitive method for measuring the thickness of thin coatings in the manufacturing industry. This encouraged us to systematically study, theoretically and experimentally, parameters that influence the fluorescence of thin layers. We analyzed the fluorescence signal as a function of the scattering and reflectance properties of the sample substrate. In addition, we investigated effects of the layer properties on fluorescence emission. A ray-tracing software is used to describe the influence of these parameters on the fluorescence emission of thin layers. Experiments using a custom-made system for imaging fluorescence analysis verify the simulations. This work shows a factor five variation of fluorescence intensity as a function of the reflectance of the sample substrate. Simulations show variations by a factor of up to eight for samples with different surface roughness. Results on tilted samples indicate a significant increase of the detected fluorescence signal, for fluorescent droplets on reflective substrates, if illuminated and coaxially observed at angles greater than 25°. These findings are of utmost relevance for all applications which utilize the fluorescence emission to quantify thin layers. These applications range from in-line lubricant monitoring in press plants to monitoring of functional coatings in medical technology and the detection of filmic contaminations.

scholarly journals Plasmon-controlled narrower and blue-shifted fluorescence emission in (Au@SiO2)SiC nanohybrids

2012 ◽  
Vol 14 (8) ◽  
Author(s):  
Ning Sui ◽  
Virginie Monnier ◽  
Yuriy Zakharko ◽  
Yann Chevolot ◽  
Sergei Alekseev ◽  
...  
Keyword(s):  
Fluorescence Emission

scholarly journals Regulation of bi-color fluorescence changes of AIE supramolecular self-assembly gels by the interaction with Al3+ and energy transfer

2021 ◽  
Author(s):  
Xinxian Ma ◽  
Jinlong Yue ◽  
Bo Qiao ◽  
LIli Zhou ◽  
Yang Gao ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Self Assembly ◽  
Fluorescence Emission ◽  
Fluorescent Materials

Supramolecular fluorescent materials have attracted considerable attention in recent years since they endow specific and unique properties to materials. Nevertheless, the utilization of photo-responsive characteristics to modulate their fluorescence emission...

scholarly journals Photophysical properties and fluorosolvatochromism of D–π–A thiophene based derivatives

RSC Advances ◽  
2020 ◽  
Vol 10 (71) ◽  
pp. 43459-43471
Author(s):  
Hussain A. Z. Sabek ◽  
Ahmed M. M. Alazaly ◽  
Dina Salah ◽  
Hesham S. Abdel-Samad ◽  
Mohamed A. Ismail ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Fluorescence Emission ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Solvation Models

Solvation-dependent photophysical properties of two push–pull thiophene-based compounds with donor–π–acceptor (D–π–A) structures were investigated using absorption, fluorescence emission and time resolved spectroscopy, and supported by different solvation models.

scholarly journals A Compact Detection Platform Based on Gradient Guided-Mode Resonance for Colorimetric and Fluorescence Liquid Assay Detection

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2797
Author(s):  
Jing-Jhong Gao ◽  
Ching-Wei Chiu ◽  
Kuo-Hsing Wen ◽  
Cheng-Sheng Huang
Keyword(s):  
Limit Of Detection ◽  
Detection System ◽  
Fluorescence Emission ◽  
Assay Sensitivity ◽  
Detection Range ◽  
Current Form ◽  
Guided Mode ◽  
Spectral Detection ◽  
Guided Mode Resonance ◽  
Colorimetric Assays

This paper presents a compact spectral detection system for common fluorescent and colorimetric assays. This system includes a gradient grating period guided-mode resonance (GGP-GMR) filter and charge-coupled device. In its current form, the GGP-GMR filter, which has a size of less than 2.5 mm, can achieve a spectral detection range of 500–700 nm. Through the direct measurement of the fluorescence emission, the proposed system was demonstrated to detect both the peak wavelength and its corresponding intensity. One fluorescent assay (albumin) and two colorimetric assays (albumin and creatinine) were performed to demonstrate the practical application of the proposed system for quantifying common liquid assays. The results of our system exhibited suitable agreement with those of a commercial spectrometer in terms of the assay sensitivity and limit of detection (LOD). With the proposed system, the fluorescent albumin, colorimetric albumin, and colorimetric creatinine assays achieved LODs of 40.99 and 398 and 25.49 mg/L, respectively. For a wide selection of biomolecules in point-of-care applications, the spectral detection range achieved by the GGP-GMR filter can be further extended and the simple and compact optical path configuration can be integrated with a lab-on-a-chip system.

scholarly journals Antibacterial activity of royal jelly-mediated green synthesized silver nanoparticles

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Susanna Gevorgyan ◽  
Robin Schubert ◽  
Mkrtich Yeranosyan ◽  
Lilit Gabrielyan ◽  
Armen Trchounian ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Green Synthesis ◽  
Royal Jelly ◽  
Fluorescence Emission ◽  
Spherical Particles ◽  
Ag Nps ◽  
Gram Negative ◽  
Green Synthesized Silver Nanoparticles ◽  
Higher Sensitivity

AbstractThe application of green synthesis in nanotechnology is growing day by day. It’s a safe and eco-friendly alternative to conventional methods. The current research aimed to study raw royal jelly’s potential in the green synthesis of silver nanoparticles and their antibacterial activity. Royal jelly served as a reducing and oxidizing agent in the green synthesis technology of colloidal silver nanoparticles. The UV–Vis maximum absorption at ~ 430 nm and fluorescence emission peaks at ~ 487 nm confirmed the presence of Ag NPs. Morphology and structural properties of Ag NPs and the effect of ultrasound studies revealed: (i) the formation of polydispersed and spherical particles with different sizes; (ii) size reduction and homogeneity increase by ultrasound treatment. Antibacterial activity of different concentrations of green synthesized Ag NPs has been assessed on Gram-negative S. typhimurium and Gram-positive S. aureus, revealing higher sensitivity on Gram-negative bacteria.

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