scholarly journals FRET Measurement of Polymer Response under Shear

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8033
Author(s):  
Ryo Iwao ◽  
Hiroki Yamaguchi ◽  
Makoto Obata ◽  
Yu Matsuda
Keyword(s):  
Energy Transfer ◽  
Shear Flow ◽  
Fluorescence Intensity ◽  
Time Variation ◽  
Diagnostic Method ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Polymer Chains ◽  
Manufacturing Processes ◽  
Spring Model

Polymer solutions under shear flow are often observed in manufacturing processes. Classically, polymer behavior is represented by Kuhn’s bead-spring model, in which only the elongation of polymer chains is assumed. In recent years, the compression of polymer chains under shear flow has been reported. In this study, we investigated the behavior of polymer chains dissolved in various concentrations under shear flow. We measured the time variation of the fluorescence intensity emitted from a FRET (fluorescence resonance energy transfer) polymer, which enabled us to study the change in the distance between both ends of a polymer chain. The polymer chains appeared to stretch and compress depending on the concentration of the polymer solution. The results showed that the deformation of polymer chains was different from the classical theory. The FRET measurement is a promising diagnostic method for understanding the dynamics of polymer chains.

Synthesis and Detection Experiments of a Biomolecule Detection Probe Based on Fluorescence Changes

2014 ◽  
Vol 998-999 ◽  
pp. 336-339
Author(s):  
Jun Wang ◽  
Da Hai Ren
Keyword(s):  
Energy Transfer ◽  
Fluorescence Intensity ◽  
Fluorescence Probe ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
High Sensitivity ◽  
Fluorescence Probes ◽  
Biomolecule Detection ◽  
Detection Probe ◽  
Higher Sensitivity

The sensitivity of fluorescence probes built upon the resonance energy transfer is not high enough at present. We built a fluorescence probe with high sensitivity (SA-488-sub-nanogold) by means of the fluorochrome Alexa488 (SA-488) labeled by streptavidin, nanogold, and biotin-subpeptide. When the fluorescence molecule SA-488 binds with the nanogold by biotin-subpeptide, the fluorescence intensity will be suppressed because of resonance energy transfer. If there are molecules under test, the energy transfer will be blocked, by which we can get the molecule content from the fluorescence intensity. Using this probe, we acquired a lower detection limit and a higher sensitivity for biotin detection.

Comparison of Fluorescence Behaviors of Rhodamine 6G with Palladium-Coated Gold Nanorods in Formations of Solutions and Thin Films

2016 ◽  
Vol 851 ◽  
pp. 14-18
Author(s):  
Nichakorn Boonpiphobanun ◽  
Pattareeya Damrongsak ◽  
Kitsakorn Locharoenrat
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Energy Transfer ◽  
Gold Nanorods ◽  
Fluorescence Intensity ◽  
Rhodamine 6G ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Optical Effect ◽  
Plasmon Resonance Energy Transfer

We have reported on the fluorescence behaviors of Rhodamine 6G with the palladium-coat gold nanorods in dichlormethane solution and in polymethylmethaceylate thin film. By monitoring the emission intensity of these samples, they show the enhancement of fluorescence intensity through the optical effect known as a plasmon resonance energy transfer. The enhancement intensity of fluorescence is enhanced up to 1.6 fold for the sample solution and 1.4 fold for the sample thin film.

A novel water-soluble quantum dot–neutral red fluorescence resonance energy transfer probe for the selective detection of megestrol acetate

2015 ◽  
Vol 39 (1) ◽  
pp. 555-565 ◽  
Author(s):  
Li-Yun Wang ◽  
Ling-Yu Dong ◽  
Luan Chen ◽  
Ya-Bing Fan ◽  
Jing Wu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Quantum Dot ◽  
Fluorescence Intensity ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Neutral Red ◽  
Water Soluble ◽  
Megestrol Acetate ◽  
Selective Detection ◽  
Concentration Levels

Megestrol acetate can specifically quench the fluorescence intensity of the β-CD-QD–NR FRET probe at low concentration levels.

scholarly journals Conformational Transitions of Polymer Chains in Solutions Characterized by Fluorescence Resonance Energy Transfer

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1007 ◽  
Author(s):  
Linlin Qin ◽  
Linling Li ◽  
Ye Sha ◽  
Ziyu Wang ◽  
Dongshan Zhou ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Resonance Energy Transfer ◽  
Conformational Changes ◽  
Conformational Transition ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Polymer Chains ◽  
Donor And Acceptor ◽  
Transition Concentration ◽  
Fluorescence Resonance

The critical overlap concentration C* is an important concept in polymer solutions and is defined as the boundary between dilute and semidilute regimes. In this study, the chain conformational changes of polystyrene (PS) with both high (Mn = 200,000 Da) and low (Mn = 13,000 Da) molecular weights in cis-decalin were compared by intrachain fluorescence resonance energy transfer (FRET). The random labeling of donor and acceptor chromophores strategy was employed for long PS chains, whereas chain-end labeling was used for short PS chains. By monitoring the spectroscopic intensity ratio between acceptor and donor, the concentration dependence on chain conformation from dilute to semidilute solutions was determined. Both long and short chains exhibit a conformational transition concentration, above which the polymer chains begin to collapse with concentration significantly. Interestingly, for randomly labeled polymer long chains, such concentration is consistent with C* determined from the viscosity result, below which only slight conformational change of polymer chain takes place. However, for the chain-end labeled short chain, the conformational transition concentration takes place earlier than C*, below which no significant polymer conformation change is observed.

scholarly journals Multichromophoric sugar for fluorescence photoswitching

2014 ◽  
Vol 10 ◽  
pp. 1471-1481 ◽  
Author(s):  
Stéphane Maisonneuve ◽  
Rémi Métivier ◽  
Pei Yu ◽  
Keitaro Nakatani ◽  
Juan Xie
Keyword(s):  
Energy Transfer ◽  
Closed Form ◽  
Uv Irradiation ◽  
Fluorescence Intensity ◽  
Cycloaddition Reaction ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Visible Irradiation ◽  
Fluorescence Photoswitching

A multichromophoric glucopyranoside 2 bearing three dicyanomethylenepyran (DCM) fluorophores and one diarylethene (DAE) photochrome has been prepared by Cu(I)-catalyzed alkyne–azide cycloaddition reaction. The fluorescence of 2 was switched off upon UV irradiation, in proportion with the open to closed form (OF to CF) conversion extent of the DAE moiety. A nearly 100% Förster-type resonance energy transfer (FRET) from all three DCM moieties to a single DAE (in its CF) moiety was achieved. Upon visible irradiation, the initial fluorescence intensity was recovered. The observed photoswiching is reversible, with excellent photo resistance.

scholarly journals Two-Step Energy Transfer Dynamics in Conjugated Polymer and Dye-Labeled Aptamer-Based Potassium Ion Detection Assay

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1206 ◽  
Author(s):  
Inhong Kim ◽  
Ji-Eun Jung ◽  
Woojin Lee ◽  
Seongho Park ◽  
Heedae Kim ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Conjugated Polymers ◽  
Fluorescence Intensity ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Fluorescence Decay ◽  
Transfer Efficiency ◽  
Detection Systems ◽  
Detection Assay ◽  
Highly Sensitive Detection

We recently implemented highly sensitive detection systems for photo-sensitizing potassium ions (K+) based on two-step Förster resonance energy transfer (FRET). As a successive study for quantitative understanding of energy transfer processes in terms of the exciton population, we investigated the fluorescence decay dynamics in conjugated polymers and an aptamer-based 6-carboxyfluorescein (6-FAM)/6-carboxytetramethylrhodamine (TAMRA) complex. In the presence of K+ ions, the Guanine-rich aptamer enabled efficient two-step resonance energy transfer from conjugated polymers to dyed pairs of 6-FAM and TAMRA through the G-quadruplex phase. Although the fluorescence decay time of TAMRA barely changed, the fluorescence intensity was significantly increased. We also found that 6-FAM showed a decreased exciton population due the compensation of energy transfer to TAMRA by FRET from conjugated polymers, but a fluorescence quenching also occurred concomitantly. Consequently, the fluorescence intensity of TAMRA showed a 4-fold enhancement, where the initial transfer efficiency (~300%) rapidly saturated within ~0.5 ns and the plateau of transfer efficiency (~230%) remained afterward.

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