FLUORESCENT-SPECTROSCOPIC RESEARCH OF IN VIVO TISSUES PATHOLOGICAL CONDITIONS

2004 ◽  
Vol 18 (06) ◽  
pp. 899-910 ◽  
Author(s):  
K. M. GIRAEV ◽  
N. A. ASHURBEKOV ◽  
R. T. MEDZHIDOV
Keyword(s):  
Steady State ◽  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Fluorescence Spectra ◽  
Respiratory Activity ◽  
Functional Condition ◽  
Excitation Wavelength ◽  
Nitrogen Laser ◽  
Pathological Conditions

The steady-state spectra of autofluorescence and the reflection coefficient on the excitation wavelength of some stomach tissues in vivo with various pathological conditions (surface gastritis, displasia, cancer) are measured under excitation by the nitrogen laser irradiation (λ ex =337.1 nm ). The contour expansion of obtained fluorescence spectra into contributions of components is conducted by the Gaussian–Lorentzian curves method. It is shown that at least 7 groups of fluorophores forming a total luminescence spectrum can be distinguished during the development of displasia and tumor processes. The correlation of intensities of flavins and NAD(P)·H fluorescence is determined and the degree of respiratory activity of cells for the functional condition considered is estimated. The evaluations of the fluorescence quantum yield of the tissue's researched are given.

scholarly journals Near-Infrared Markers based on Bacterial Phytochromes with Phycocyanobilin as a Chromophore

2019 ◽  
Vol 20 (23) ◽  
pp. 6067 ◽  
Author(s):  
Olesya V. Stepanenko ◽  
Olga V. Stepanenko ◽  
Olesya G. Shpironok ◽  
Alexander V. Fonin ◽  
Irina M. Kuznetsova ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Cell Biology ◽  
Fluorescence Spectra ◽  
Near Infrared ◽  
Biological Tissues ◽  
Lower Mobility ◽  
High Fluorescence ◽  
Bacterial Phytochromes

Biomarkers engineered on the basis of bacterial phytochromes with biliverdin IXα (BV) cofactor as a chromophore are increasingly used in cell biology and biomedicine, since their absorption and fluorescence spectra lie within the so-called optical “transparency window” of biological tissues. However, the quantum yield of BV fluorescence in these biomarkers does not exceed 0.145. The task of generating biomarkers with a higher fluorescence quantum yield remains relevant. To address the problem, we proposed the use of phycocyanobilin (PCB) as a chromophore of biomarkers derived from bacterial phytochromes. In this work, we characterized the complexes of iRFP713 evolved from RpBphP2 and its mutant variants with different location of cysteine residues capable of covalent tetrapyrrole attachment with the PCB cofactor. All analyzed proteins assembled with PCB were shown to have a higher fluorescence quantum yield than the proteins assembled with BV. The iRFP713/V256C and iRFP713/C15S/V256C assembled with PCB have a particularly high quantum yield of 0.5 and 0.45, which exceeds the quantum yield of all currently available near-infrared biomarkers. Moreover, PCB has 4 times greater affinity for iRFP713/V256C and iRFP713/C15S/V256C proteins compared to BV. These data establish iRFP713/V256C and iRFP713/C15S/V256C assembled with the PCB chromophore as promising biomarkers for application in vivo. The analysis of the spectral properties of the tested biomarkers allowed for suggesting that the high-fluorescence quantum yield of the PCB chromophore can be attributed to the lower mobility of the D-ring of PCB compared to BV.

UV-Trained and Metal-Enhanced Fluorescence of Biliverdin and Biliverdin Nanoparticles

Nanoscale ◽  
2021 ◽  
Author(s):  
Parinaz Fathi ◽  
Ayman Roslend ◽  
Kritika Mehta ◽  
Parikshit Moitra ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Biomedical Imaging ◽  
Enhanced Fluorescence ◽  
Metal Enhanced Fluorescence

Increasing the fluorescence quantum yield of fluorophores is of great interest for in vitro and in vivo biomedical imaging applications. At the same time, photobleaching and photodegradation resulting from continuous...

scholarly journals Fiber-Optic Time-Resolved Fluorescence Sensor for in Vitro Serotonin Determination

1993 ◽  
Vol 47 (5) ◽  
pp. 590-597 ◽  
Author(s):  
Stephane Mottin ◽  
Canh Tran-Minh ◽  
Pierre Laporte ◽  
Raymond Cespuglio ◽  
Michel Jouvet
Keyword(s):  
Chemical Sensor ◽  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
Excitation Wavelength ◽  
Nitrogen Laser ◽  
Time Resolved ◽  
Temporal Effects ◽  
Starting Point

At pH 7 and with the excitation at wavelengths above 315 nm, previously unreported fluorescence of 5-HT (5-hydroxytryptamine) is observed. Two fluorescence bands were observed for 5-HT; the first emits at around 390 nm with an associated lifetime near 1 ns, and the other (well known) emits at 340 nm with an associated lifetime of 2.7 ns. With both static and time-resolved fluorescences, the spectral and temporal effects of the excitation wavelength were studied between 285 and 340 nm. With these basic spectroscopic properties as a starting point, a fiber-optic chemical sensor (FOCS) was developed in order to measure 5-HT with a single-fiber configuration, nitrogen laser excitation, and fast digitizing techniques. Temporal effects including fluorescence of the optical fiber were studied and compared with measurements both directly in cuvette and through the fiber-optic sensor. Less than thirty seconds are required for each measurement. A detection limit of 5-HT is reached in the range of 5 μM. Our system, with an improved sensitivity, could therefore be a possible and convenient “tool” for in vivo determination of 5-HT.

scholarly journals Excitation-Dependent Fluorescence Quantum Yield for Freshwater Chromophoric Dissolved Organic Matter from Northern Russian Lakes

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Svetlana Patsaeva ◽  
Daria Khundzhua ◽  
Oleg A. Trubetskoj ◽  
Olga E. Trubetskaya
Keyword(s):  
Organic Matter ◽  
Quantum Yield ◽  
Dissolved Organic Matter ◽  
Fluorescence Quantum Yield ◽  
Molecular Size ◽  
Reversed Phase ◽  
Chromophoric Dissolved Organic Matter ◽  
Excitation Wavelength ◽  
Fluorescence Detector ◽  
Wide Range

Advanced fluorescence analysis within the wide range of excitation wavelengths from 230 to 510 nm accompanied with chromatography was used to study natural chromophoric dissolved organic matter (CDOM) from three freshwater Karelian lakes. The influence of excitation wavelength (λex) on fluorescence quantum yield and emission maximum position was determined. The CDOM fluorescence quantum yield has reached a minimum at λex∼270–280 nm and a maximum at λex∼340–360 nm. It was monotonously decreasing after 370 nm towards longer excitation wavelengths. Analytical reversed-phase high-performance liquid chromatography with multiwavelength fluorescence detector characterized distribution of fluorophores between hydrophilic/hydrophobic CDOM parts. This technique revealed “hidden” protein-like fluorophores for some CDOM fractions, in spite of the absence of protein-like fluorescence in the initial CDOM samples. The humic-like fluorescence was documented for all hydrophilic and hydrophobic CDOM chromatographic peaks, and its intensity was decreasing along with peaks’ hydrophobicity. On contrary, the protein-like fluorescence was found only in the hydrophobic peaks, and its intensity was increasing along with peaks’ hydrophobicity. This work provides new data on the CDOM optical properties consistent with the formation of supramolecular assemblies controlled by association of low-molecular size components. In addition, these data are very useful for understanding the CDOM function in the environment.

Changes of Excitation Spectra of in vivo Chlorophyll Fluorescence during Induction of Photosynthesis

1993 ◽  
Vol 48 (1-2) ◽  
pp. 46-51 ◽  
Author(s):  
Wieslaw I. Gruszecki ◽  
Zbigniew Krupa
Keyword(s):  
Energy Transfer ◽  
Chlorophyll Fluorescence ◽  
Quantum Yield ◽  
Dark Adaptation ◽  
Fluorescence Quantum Yield ◽  
Excitation Energy Transfer ◽  
Reaction Centers ◽  
Excitation Spectra ◽  
In Vivo Chlorophyll Fluorescence

Excitation spectra of chlorophyll fluorescence from intact rye leaves were registered at different steps of the induction of photosynthesis after dark adaptation. Analysis of these spectra indicates that at least two processes related to spectroscopic features are responsible for a fluorescence quenching. The first one, active during the first 100 s of illumination, was interpreted to consists in an overall decrease of the fluorescence quantum yield of antenna pigments and chlorophylls, in particular close to the reaction centers. The second type of a fluorescence decrease (between 100 s and 300 s of illumination) was found to be in large extent related to decrease of the rate of an excitation energy transfer between accessory xanthophyll pigments and chlorophylls emitting fluorescence. This latter molecular mechanism is discussed as being related to violaxanthin availability to de-epoxidation in the xanthophyll cycle.

Synthesis and Spectroscopic Properties of a Novel Bifunctional Pyrene Derivative and its Incorporation into OligoDNA

2015 ◽  
Vol 68 (2) ◽  
pp. 256 ◽  
Author(s):  
Tomohisa Moriguchi ◽  
Satomi Hida ◽  
Fumio Yoneda ◽  
Kazuo Shinozuka
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Fluorescence Spectra ◽  
Bathochromic Shift ◽  
Spectroscopic Properties ◽  
Absorption And Fluorescence Spectra ◽  
Electron Withdrawing Group

A new pyrene derivative bearing a modifiable silyl function (electron-donating group) and cyano function (electron-withdrawing group) was synthesized as a labelling agent for biological substances. The modified pyrene exhibited a marked bathochromic shift in both absorption and fluorescence spectra. The fluorescence quantum yield of the modified pyrene was also significantly increased compared with that of the unmodified pyrene. The modified pyrene was successfully incorporated into oligoDNA.

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