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1
Windsor, S. A., N. J. Harrison i M. H. Tinker. "Electro-fluorescence studies of the binding of fluorescent dyes to sepiolite". Clay Minerals 31, nr 1 (marzec 1996): 81–94. http://dx.doi.org/10.1180/claymin.1996.031.1.08.
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AbstractAqueous suspensions of sepiolite, tagged with fluorescent dyes, have been studied using electro-fluorescence polarization spectroscopy. The binding modes of some 37 fluorescent dyes and optical brightening agents to the rod-like sepiolite particles have been determined. Many of the dyes are found to bind with a degree of order to the clay particle's major axis. The binding geometries of the cationic dye molecules tested were found to be dependent upon molecular size. This supports the view that these cationic dye molecules are constrained within the channels which are characteristic of the mineral sepiolite. Results for uncharged and anionic dye molecules are also presented; no dependence of binding geometry upon molecular size was found. The anionic molecules are most likely to associate with the exterior cationic magnesium surface. The results indicate that some of the anionic dyes are too large to fit in the channels. Some of the uncharged molecules adopt a number of orientations upon binding which gives rise to an average geometry being observed for these dyes.
2
Collings, David A. "Anthocyanin in the Vacuole of Red Onion Epidermal Cells Quenches Other Fluorescent Molecules". Plants 8, nr 12 (12.12.2019): 596. http://dx.doi.org/10.3390/plants8120596.
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Peels from the inner epidermis of onion bulbs are a model system in plant cell biology. While the inner epidermis of red onions is characteristically white, small patches of cells sometimes redden, containing vacuolar anthocyanin. This study investigated the spectroscopic properties of these anthocyanic cells. When fluorescent dyes were loaded into the vacuole of onion epidermal cells, the anthocyanic cells showed decreased dye fluorescence. This decrease was observed for fluorescein and carboxyfluorescein that are pumped into the vacuole by anion transporters, for acridine orange which acid loads into the vacuole, and for the fluorescent sugar analogue esculin loaded into the vacuole by sucrose transporters. Similar decreases in carboxyfluorescein fluorescence were observed when dye was loaded into the vacuoles of several other plant species, but decreases were not observed for dyes resident in the tonoplast membrane. As cellular physiology was unaffected in the anthocyanic cells, with cytoplasmic streaming, vacuolar and cytoplasmic pH not being altered, the decreased dye fluorescence from the anthocyanic cells can be attributed to fluorescence quenching. Furthermore, because quenching decreased with increasing temperature. It was concluded, therefore, that vacuolar anthocyanin can statically quench other fluorescent molecules in vivo, an effect previously demonstrated for anthocyanin in vitro.
3
Wu, Jian, Yongjun Du, Chunyan Wang i Tao Chen. "The Detection of a Fluorescent Dye by Surface-Enhanced Fluorescence with the Addition of Silver Nanoparticles and Its Application for the Space Station". Journal of Nanoscience and Nanotechnology 20, nr 5 (1.05.2020): 3195–200. http://dx.doi.org/10.1166/jnn.2020.17383.
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Surface-enhanced fluorescence detection has large potential for detecting many chemical and biological trace analytes. This paper presents a novel method for preparing silver nanomaterials in microfluidic chip channels for the surface-enhanced fluorescence detection of fluorescent dye (SYBR Green I) molecules. Microfluidic chip channels were fabricated by a 248-nm excimer laser. Silver nanoparticles (Ag-NPs) were prepared inside the microfluidic chip channels by directly heating the silver precursor solution. The influence of different temperatures on the sizes of the silver nanoparticles was studied. Then, the surface-enhanced fluorescence technology based on the microfluidic system was used to detect the fluorescent dye molecules. As a result, the fluorescence signal of the fluorescent dye molecules was significantly enhanced by the silver nanoparticles. In addition, the effect of particle size on the fluorescence signal was studied. This simple and fast method is suitable for a fluorescent PCR (polymerase chain reaction) system and has good application prospects for detecting harmful microorganisms in a spacecraft.
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Kurumida, Yoichi, i Nobuhiro Hayashi. "Development of a Novel Q-body Using an In Vivo Site-Specific Unnatural Amino Acid Incorporation System". Sensors 18, nr 8 (1.08.2018): 2519. http://dx.doi.org/10.3390/s18082519.
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A Q-body capable of detecting target molecules in solutions could serve as a simple molecular detection tool. The position of the fluorescent dye in a Q-body affects sensitivity and therefore must be optimized. This report describes the development of Nef Q-bodies that recognize Nef protein, one of the human immunodeficiency virus (HIV)’s gene products, in which fluorescent dye molecules were placed at various positions using an in vivo unnatural amino acid incorporation system. A maximum change in fluorescence intensity of 2-fold was observed after optimization of the dye position. During the process, some tryptophan residues of the antibody were found to quench the fluorescence. Moreover, analysis of the epitope indicated that some amino acid residues of the antigen located near the epitope affected the fluorescence intensity.
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Guo, Xiang-Qun, Zu-Lin Zhang, Yi-Bing Zhao, Dong-Yuan Wang i Jin-Gou Xu. "DNA—Dye Fluorescence Enhancement Based on Shifting the Dimer—Monomer Equilibrium of Fluorescent Dye". Applied Spectroscopy 51, nr 7 (lipiec 1997): 1002–7. http://dx.doi.org/10.1366/0003702971941386.
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In this paper, the investigation of DNA–dye fluorescence enhancement based on shifting the dimer–monomer equilibrium of a fluorescent dye, acridine orange (AO), is reported. Formation of a virtually nonfluorescent dimeric dye, acridine orange homodimer (AOAO), induced by the pre-micellar aggregation of an anionic surfactant, sodium dodecyl sulfate (SDS), was observed. The possibility of using the in situ formed AOAO as a fluorescent probe for nucleic acids and polynucleotides was studied. The results showed that a nearly 1000-fold fluorescence enhancement was observed upon addition of calf thymus DNA (CT DNA). The fluorescence enhancement effect of DNA was thought to be based on the DNA modulated shift of the dimmer monomer equilibrium of AO in the anionic surfactant solution. Intercalation of the monomer in DNA caused the dissociation of AOAO and led to a very high fluorescence enhancement. It seemed that the dimeric dye molecules acted as a source of monomer molecules ready for interacting with nucleic acids and, at the same time, decreased the inherent fluorescence of monomer molecules, which proved to be unfavorable to the detection of fluorescence enhancement. A linear dependence of fluorescence intensity on CT DNA concentration over a range from 7.8 ng/mL to 10.0 g/mL, in the presence of AO at a concentration of 1.65 × 10−6mol/L and of SDS at a concentration of 8.0 × 10−4 mol/L, allowed sensitive quantitation of CT DNA in a conventional fluorometer. Calibration graphs for yeast RNA and polynucleotides, such as poly A, poly U, and poly I, were also obtained.
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Fratoddi, Ilaria, Chiara Battocchio, Giovanna Iucci, Daniele Catone, Antonella Cartoni, Alessandra Paladini, Patrick O’Keeffe, Silvia Nappini, Sara Cerra i Iole Venditti. "Silver Nanoparticles Functionalized by Fluorescein Isothiocyanate or Rhodamine B Isothiocyanate: Fluorescent and Plasmonic Materials". Applied Sciences 11, nr 6 (10.03.2021): 2472. http://dx.doi.org/10.3390/app11062472.
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This paper presents the synthesis of silver nanoparticles (AgNPs) functionalized with fluorescent molecules, in particular with xanthene-based dyes, i.e., fluorescein isothiocyanate (FITC, λmax = 485 nm) and rhodamine B isothiocyanate (RITC, λmax = 555 nm). An in-depth characterization of the particle–dye systems, i.e., AgNPs–RITC and AgNPs–FITC, is presented to evaluate their chemical structure and optical properties due to the interaction between their plasmonic and absorption properties. UV–Vis spectroscopy and the dynamic light scattering (DLS) measurements confirmed the nanosize of the AgNPs–RITC and AgNPs–FITC. Synchrotron radiation X-ray photoelectron spectroscopy (SR-XPS) was used to study the chemical surface functionalization by structural characterization, confirming/examining the isothiocyanate–metal interaction. For AgNPs–RITC, in which the plasmonic and fluorescence peak are not superimposed, the transient dynamics of the dye fluorescence were also studied. Transient absorption measurements showed that by exciting the AgNPs–RITC sample at a wavelength corresponding to the AgNP plasmon resonance, it was possible to preferentially excite the RITC dye molecules attached to the surface of the NPs with respect to the free dye molecules in the solution. These results demonstrate how, by combining plasmonics and fluorescence, these AgNPs can be used as promising systems in biosensing and imaging applications.
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Liu, Wenjing, Huabin Li, Yanmin Huo, Qingxia Yao i Wenzeng Duan. "Recent Progress in Research on [2.2]Paracyclophane-Based Dyes". Molecules 28, nr 7 (23.03.2023): 2891. http://dx.doi.org/10.3390/molecules28072891.
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In recent years, the [2.2]paracyclophane (PCP) ring has attracted extensive attention due to its features of providing not only chirality and electron-donating ability but also steric hindrance, which reduces intermolecular π–π stacking interactions and thereby improves the fluorescence properties of dyes. To date, some circularly polarized luminescence (CPL)-active small organic molecules based on the PCP skeleton have been reviewed; however, the application of the PCP ring in improving the photophysical properties of fluorescent dyes is still limited, and new molecular design strategies are still required. This review summarizes and promotes the application of PCP in fluorescent dye design, fluorescence detection, and CPL modulation. We expect that this review will provide readers with a comprehensive understanding of the PCP skeleton and lead to further improvement in fluorescent dye design.
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Middleton, G. W., i B. R. Jennings. "Electrofluorescence of dye-tagged sepiolite". Clay Minerals 26, nr 1 (marzec 1991): 1–9. http://dx.doi.org/10.1180/claymin.1991.026.1.01.
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AbstractIn electric fields, anisodiametric mineral particles in suspension orientate and align. When tagged with fluorescent molecules, the alignment is accompanied by changes in the intensities of the polarized components of the emitted fluorescence. By measuring these changes under specific experimental conditions, any non-random directional coincidence of the absorption and emission transition moments associated with the dye molecules can be evaluated and the spatial array of the dyes estimated. From such measurements, the binding of the optical brightening agent FBA1, a triazinylaminostilbene compound, to sepiolite has been studied.
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Aristova, D., G. Volynets, S. Chernii, M. Losytskyy, A. Balanda, Yu Slominskii, A. Mokhir, S. Yarmoluk i V. Kovalska. "Far-red pentamethine cyanine dyes as fluorescent probes for the detection of serum albumins". Royal Society Open Science 7, nr 7 (lipiec 2020): 200453. http://dx.doi.org/10.1098/rsos.200453.
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Benzothiazole based cyanine dyes with bridged groups in the pentamethine chain were studied as potential far-red fluorescent probes for protein detection. Spectral-luminescent properties were characterized for unbound dyes and in the presence of serum albumins (bovine (BSA), human (HSA), equine (ESA)), and globular proteins (β-lactoglobulin, ovalbumin). We have observed that the addition of albumins leads to a significant increase in dyes fluorescence intensity. However, the fluorescent response of dyes in the presence of other globular proteins was notably lower. The value of fluorescence quantum yield for dye bearing a sulfonate group complexed with HSA amounted to 42% compared with 0.2% for the free dye. The detection limit of HSA by this dye was greater than 0.004 mg ml −1 which indicates the high sensitivity of dye to low HSA concentrations. Modelling of structure of the dyes complexes with albumin molecules was performed by molecular docking. According to these data, dyes could bind to up to five sites on the HSA molecule; the most preferable are the haemin-binding site in subdomain IB and the dye-binding site in the pocket between subdomains IA, IIA and IIIA. This work confirms that pentamethine cyanine dyes could be proposed as powerful far-red fluorescent probes applicable for highly sensitive detection of albumins.
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Tran, Vien Thi, i Heongkyu Ju. "Fluorescence Enhancement via Dual Coupling of Dye Molecules with Silver Nanostructures". Chemosensors 9, nr 8 (10.08.2021): 217. http://dx.doi.org/10.3390/chemosensors9080217.
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We demonstrate the enhancement of fluorescence emitted from dye molecules coupled with two surface plasmons, i.e., silver nanoparticles (AgNPs)-induced localized surface plasmons (LSP) and thin silver (Ag) film supported surface plasmons. Excitation light is illuminated to a SiO2 layer that contains both rhodamine 110 molecules and AgNPs. AgNPs enhances excitation rates of dye molecules in their close proximity due to LSP-induced enhancement of local electromagnetic fields at dye excitation wavelengths. Moreover, the SiO2 layer on one surface of which a 50 nm-thick Ag film is coated for metal cladding (air on the other surface), acts as a waveguide core at the dye emission wavelengths. The Ag film induces the surface plasmons which couple with the waveguide modes, resulting in a waveguide-modulated version of surface plasmon coupled emission (SPCE) for different SiO2 thicknesses in a reverse Kretschmann configuration. We find that varying the SiO2 thickness modulates the fluorescent signal of SPCE, its modulation behavior being in agreement with the theoretical simulation of thickness dependent properties of the coupled plasmon waveguide resonance. This enables optimization engineering of the waveguide structure for enhancement of fluorescent signals. The combination of LSP enhanced dye excitation and the waveguide-modulated version of SPCE may offer chances of enhancing fluorescent signals for a highly sensitive fluorescent assay of biomedical and chemical substances.
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Aleksakhina, E. L., Yu S. Marfin, D. A. Merkushev, I. K. Tomilova i E. V. Rumyantsev. "Studying the blood clotting investigation in prescence of boron-dipyrrin fluorescent dyes". Kazan medical journal 96, nr 5 (15.10.2015): 792–98. http://dx.doi.org/10.17750/kmj2015-792.
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Aim. To study the blood clotting in prescence of boron-dipyrrin fluorescent dyes. Methods. Photophysical properties of several boron-dippiryn based fluorescent dyes were examined in presence of blood plasma biomolecules and in model system containing bovine serum albumin using electron absorption spectroscopy and fluorescence spectroscopy. Results. The interaction between the investigated dyes and protein plasma components changes spectral characteristics of the dyes and leads to bathochromic and hypochromic shifts of absorption spectra accompanied by changing of fluorescence intensity. The mechanism of fluorescence changing was defined within the Stern-Folmer theory. It was shown that the static factor prevails due to dye-biopolymers molecular complex formation at plasma protein concentration up to 1 g/l, while the higher levels are characterized mainly by nonspecific interactions of fluorophores. The increase of fluorescent characteristics of phenyl-substituted BODIPY in the presence of proteins caused by resonance energy transfer and physicochemical features changes of the fluorophore molecular environment was shown. Conclusion. The gained results demonstrate the possibility of using the BODIPY dye for determination of blood clotting activity. Specific interactions of dye molecules with studied biological objects allows to analyze the contents and dynamic processes in biological objects at blood serum clotting.
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Maskevich, Alexander A. "Fluorescent properties anionic derivative of thioflavin T". Journal of the Belarusian State University. Physics, nr 2 (20.05.2021): 4–14. http://dx.doi.org/10.33581/2520-2243-2021-2-4-14.
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We have investigated the spectral properties of a new benzothiazole dye – a thioflavin T derivative – 3-sulfopropyl-5-methoxy-2-[3-(3,5-diethyl-2-benzothiazolidene)-1-propienyl]-benzothiazolium (Th-C11). Based on quantum-chemical calculations, it is shown that the molecule in the ground state has a flat structure. In an excited state, the minimum energy corresponds to a twisted conformation, in which the aromatic fragments are arranged orthogonally. Since the twisted state is non-fluorescent, the transition to this state (torsion relaxation) is a quenching process. Th-C11 dye exhibits the properties of a fluorescent molecular rotor. As a result of experimental studies, it was found that torsion relaxation of molecular fragments is the main process that determines the strong dependence of the quantum yield and the duration of fluorescence decay on the viscosity of the solvent. A characteristic feature of this dye is the sensitivity of the fluorescence parameters – the quantum yield, the decay duration and the position of the spectrum not only to the viscosity, but also to the polarity of the medium. The paper also explains the dependence of the position of the absorption and fluorescence spectra on the polarity and viscosity of the solvent as a result of the manifestation of the processes of torsion and solvation relaxation of the chromophore and solvent molecules.
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Lu, Yanjiao, Bicheng He, Zhuo Gao, Jie Li, Jie Shen, Wantai Yang i Meizhen Yin. "One-Pot Synthesis of Cy5-Encapsulated Photostable Fluorescent Silica Nanoparticles for Bioimaging". Nano LIFE 05, nr 03 (wrzesień 2015): 1540007. http://dx.doi.org/10.1142/s1793984415400073.
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A new type of Cy5-encapsulated photostable fluorescent silica nanoparticles (FSNPs) bearing positive charges have been successfully fabricated by a reverse microemulsion synthesis in one-pot. The Cy5 dye containing four primary amines are embedded into silica via covalent bonds through a silane coupling agent (GPTMS), followed by co-condensation with tetraethylorthosilicate. The uniform-sized, spherical and monodispersed FSNPs have high fluorescence intensity and photostability. The FSNPs exhibit high stability, good biocompatibility as well as low cytotoxicity. These FSNPs can be internalized into live cells and thus fluorescently label the cells. This study provides a simple synthesis approach that can be applied to other water-soluble and amino-modified organic dye molecules for biological targeting and fluorescent cell imaging.
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Cho, Y. S. "Fabrication Of Colloidal Clusters Decorated With Dye Molecules For Potential Application As Photonic Molecules". Archives of Metallurgy and Materials 60, nr 2 (1.06.2015): 1221–25. http://dx.doi.org/10.1515/amm-2015-0102.
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AbstractIn this study, colloidal clusters decorated with fluorescent dyes were fabricated by evaporation-driven self-assembly using emulsion droplets as confining geometries. Silica microspheres were synthesized by Stober method followed by the modification with dye molecules through additional surface sol-gel reaction for the formation of thin silica shell. The surface of the resultant dye-doped silica microspheres was modified with hydrophobic silane coupling agent to disperse the particle suspension in organic solvent such as hexane. The fluorescent silica microspheres were self-assembled inside oil-in-water emulsions by evaporation-driven self-assembly for the formation of colloidal clusters, potentially applicable for photonic molecules. The clusters with fluorescent emission were observed using confocal microscope.
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Rohrer, Jurg, Jeanne Elia i Jacob Rabenstein. "Optimization of loading conditions for a violet dye for use in cell proliferation studies (65.9)". Journal of Immunology 186, nr 1_Supplement (1.04.2011): 65.9. http://dx.doi.org/10.4049/jimmunol.186.supp.65.9.
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Abstract Fluorescein diacetate (FDA) and its derivatives, such as carboxyfluorescein succinimidyl ester (CFSE) are nonfluorescent molecules that diffuse into cells and are hydrolyzed by intracellular non-specific esterases to become fluorescent by-products. These fluorescent dye molecules accumulate only in live cells with intact cell membranes and active esterases, while dead cells remain non fluorescent. The precise kinetics of membrane transport and intracellular hydrolysis of FDA and its analogs are related to cellular functions. FDA dyes have been shown to have multiple uses which include, in vitro or in vivo cell tracking experiments and cell proliferation. BD Horizon™ Violet Proliferation Dye (VPD450) dye contains both an esterase-cleavable and an amine-reactive succinimidyl ester group. This dye can be used in multicolor flow cytometry applications with GFP or FITC-labeled cells. Optimization of cell and dye concentrations are important considerations in experimental design with all FDA-based proliferation dyes. A comparison study was performed to determine the effects VPD450 dye loading on cell proliferation, apoptosis, and cell signaling.
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Eder, Ann-Christin, Jessica Matthias, Martin Schäfer, Jana Schmidt, Nils Steinacker, Ulrike Bauder-Wüst, Lisa-Charlotte Domogalla i in. "A New Class of PSMA-617-Based Hybrid Molecules for Preoperative Imaging and Intraoperative Fluorescence Navigation of Prostate Cancer". Pharmaceuticals 15, nr 3 (22.02.2022): 267. http://dx.doi.org/10.3390/ph15030267.
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The development of PSMA-targeting low-molecular-weight hybrid molecules aims at advancing preoperative imaging and accurate intraoperative fluorescence guidance for improved diagnosis and therapy of prostate cancer. In hybrid probe design, the major challenge is the introduction of a bulky dye to peptidomimetic core structures without affecting tumor-targeting properties and pharmacokinetic profiles. This study developed a novel class of PSMA-targeting hybrid molecules based on the clinically established theranostic agent PSMA-617. The fluorescent dye-bearing candidates of the strategically designed molecule library were evaluated in in vitro assays based on their PSMA-binding affinity and internalization properties to identify the most favorable hybrid molecule composition for the installation of a bulky dye. The library’s best candidate was realized with IRDye800CW providing the lead compound. Glu-urea-Lys-2-Nal-Chx-Lys(IRDye800CW)-DOTA (PSMA-927) was investigated in an in vivo proof-of-concept study, with compelling performance in organ distribution studies, PET/MRI and optical imaging, and with a strong PSMA-specific tumor uptake comparable to that of PSMA-617. This study provides valuable insights about the design of PSMA-targeting low-molecular-weight hybrid molecules, which enable further advances in the field of peptidomimetic hybrid molecule development.
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Ha, Chu Viet, J. C. Brochon i Tran Hong Nhung. "Influence of Surface Plasmon Resonance on Fluorescence Emission of Dye-doped Nanoparticles". Communications in Physics 24, nr 3S2 (20.04.2016): 121–29. http://dx.doi.org/10.15625/0868-3166/24/3s2/5057.
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The influence of the surface plasmon of gold nanoparticles on the optical properties of the fluorescent nanoparticles in aqueous solution have been investigated. The fluorescence of nanoparticles can be enhanced or quenched in the presence of gold nanoparticles depending on the domination of energy transfer mechanisms: radiating surface plasmon coupling emission or F\"{o}rster energy transfer from fluorescent particles to gold particles, which exciting absorbing plasmon. The fluorescence enhancement or quenching is attributed to the increase or decrease of radiative recombination rates, respectively. The parameters of the energy transfer between fluorescent nanoparticles (dye molecules encapsulated in silica nanoparticles) and nano golds have been estimated. The results show that the interactions between nanoparticles depend on the size of both fluorophores (as donors) and gold nanoparticles (as acceptors).
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Nesterov, Pavel V., Vladimir V. Shilovskikh, Alexander D. Sokolov, Vladislav V. Gurzhiy, Alexander S. Novikov, Alexandra A. Timralieva, Elena V. Belogub, Nikolay D. Kondratyuk, Nikita D. Orekhov i Ekaterina V. Skorb. "Encapsulation of Rhodamine 6G Dye Molecules for Affecting Symmetry of Supramolecular Crystals of Melamine-Barbiturate". Symmetry 13, nr 7 (23.06.2021): 1119. http://dx.doi.org/10.3390/sym13071119.
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Supramolecular organic systems can be used as a host for the encapsulation of small organic molecules. Here, we chose melamine barbiturate as a robust system capable of supramolecular assembly and the Rhodamine 6G dye entrapment as a guest molecule. The encapsulation of the dye was investigated by UV-visible spectroscopy, SEM and optical fluorescent microscopy while the insight into the crystal structure of the system was obtained by single crystal and powder XRD. For investigation of the system’s properties on a molecular level, the DFT and Classical Molecular Dynamics methods were utilized. Surprisingly, both theoretical and experimental data show not only the successful encapsulation of Rhodamine 6G molecules inside the supramolecular assembly, but also that inclusion of such molecules leads to the drastic improvement in the organic crystal shape. The melamine barbiturate in presence of the Rhodamine 6G molecules tend to form crystals with lesser degree of twinning and higher symmetry in shape than the ones without dye molecules.
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Alyamani, Baraa J., Omar A. Alsager i Mohammed Zourob. "Label-Free Fluorescent Aptasensor for Small Targets via Displacement of Groove Bound Curcumin Molecules". Sensors 19, nr 19 (26.09.2019): 4181. http://dx.doi.org/10.3390/s19194181.
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Signal transduction based on fluorescence is one of the most common optical aptasensors for small molecules. Sensors with a number of unique features including high sensitivity, low cost, and simple operation can be constructed easily. However, the label-free fluorescent approach is limited to synthetic dyes that bind strongly to the aptamer sequence and result in a diminished sensor operation with high detection limits. In this study, we report the use of curcumin as a fluorescent probe to signal aptamer/small target binding events. A substantial enhancement in curcumin’s fluorescent emission was observed when bound into the grooves of vitamin D3 (VTD3) binding aptamer, as an example. However, the introduction of the target molecule causes the aptamer to undergo a conformational change that favors complexing the target molecule over binding the curcumin dye. The sensor was able to detect VTD3 down to 1 fM concentration in buffer solutions and extracted blood samples, operate at a wide dynamic range, and discriminate against potential biological interfering molecules including VTD2. The operation of the curcumin based fluorescent sensor is at least six orders of magnitude more sensitive than a VTD3 sensor constructed with the synthetic dye SYBR Green I. The generality of the reported label-free approach was applied with a previously isolated 75-mer bisphenol-A (BPA) aptamer, confirming that the reported sensing strategy is not confined on a particular aptamer sequence. Our work not only reports a novel sensor format for the detection of small molecules, but also serves fluorescent sensor’s most pressing need being novel fluorophores for multiplex targets detection.
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Peerzade, Saquib, Nadezhda Makarova i Igor Sokolov. "Ultrabright Fluorescent Silica Nanoparticles for Dual pH and Temperature Measurements". Nanomaterials 11, nr 6 (9.06.2021): 1524. http://dx.doi.org/10.3390/nano11061524.
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The mesoporous nature of silica nanoparticles provides a novel platform for the development of ultrabright fluorescent particles, which have organic molecular fluorescent dyes physically encapsulated inside the silica pores. The close proximity of the dye molecules, which is possible without fluorescence quenching, gives an advantage of building sensors using FRET coupling between the encapsulated dye molecules. Here we present the use of this approach to demonstrate the assembly of ultrabright fluorescent ratiometric sensors capable of simultaneous acidity (pH) and temperature measurements. FRET pairs of the temperature-responsive, pH-sensitive and reference dyes are physically encapsulated inside the silica matrix of ~50 nm particles. We demonstrate that the particles can be used to measure both the temperature in the biologically relevant range (20 to 50 °C) and pH within 4 to 7 range with the error (mean absolute deviation) of 0.54 °C and 0.09, respectively. Stability of the sensor is demonstrated. The sensitivity of the sensor ranges within 0.2–3% °C−1 for the measurements of temperature and 2–6% pH−1 for acidity.
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Park, Doo Hong, Se Bin Oh i Sung Chul Hong. "In Situ Fluorescent Illumination of Microplastics in Water Utilizing a Combination of Dye/Surfactant and Quenching Techniques". Polymers 14, nr 15 (29.07.2022): 3084. http://dx.doi.org/10.3390/polym14153084.
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Although plastics have benefited our lives in terms of cost and convenience, the disposal of end-of-life plastics poses environmental problems, such as microplastics (MPs). Although the separation (e.g., filtration) and staining of MPs with fluorescent dye/solvent are generally accepted steps to observe MPs in an environmental matrix, in this study, an in situ selective fluorescent illumination of the MPs in water was attempted with the aid of surfactant. Nonpolar fluorescent dye in combination with surfactant affords nanometer-sized dye particles in water, which adsorb on MPs and penetrate the polymer matrix for effective staining and stable fluorescent behaviors. The effects of different staining parameters, including different dyes, surfactants, staining temperatures, staining times, dye/surfactant ratios, dye/MP ratios, and MP concentrations in aqueous solutions were investigated to better understand staining conditions. More interestingly, non-adsorbed free dye molecules in the staining solution were almost completely fluorescence-quenched by introducing the quenching agent, aniline, while the fluorescence intensity of the stained MP was maintained. By staining MPs with a dye/surfactant combination and subsequently quenching with aniline, in situ selective fluorescent illumination of the MPs in water was successfully achieved, which may eliminate the tedious separation/filtration procedure of MPs to accomplish the quick detection or monitoring of MPs.
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Kolyvanova, Maria A., Mikhail A. Klimovich, Ekaterina D. Koshevaya, Evgeny A. Nikitin, Nikita S. Lifanovsky, Vladimir Y. Tyurin, Alexandr V. Belousov, Aleksei V. Trofimov, Vladimir A. Kuzmin i Vladimir N. Morozov. "Chemical Dosimetry Using Bisbenzimidazoles: Solvent-Dependent Fluorescence Response of Hoechst 33258 to Radiation Exposure". Photonics 10, nr 6 (9.06.2023): 671. http://dx.doi.org/10.3390/photonics10060671.
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Bisbenzimidazoles have a broad spectrum of potential applications: radioprotectors, drug delivery vectors, antiviral agents, etc. At the same time, they seem to be promising fluorescent probes for radiation measurements. Therefore, in the present work, a fluorescent response to X-ray irradiation of Hoechst 33258, one of the most widely known representatives of the bisbenzimidazole family, was studied for the first time. Irradiation of the dye was performed in aqueous and organic solutions (DMSO and glycerol), as well as in their mixtures. It is shown that the reaction of the dye to radiation exposure is very versatile and may be controlled by the solvent properties, which makes it possible to build relationships between the absorbed dose and a wide variety of parameters of its fluorescence signal. For example, irradiation may induce fluorescence quenching caused by the degradation of the dye, a change in the position of the fluorescence band maximum due to the modification of the dye molecules or to the radiation-induced changes in the properties of the medium, as well as a fluorescence flare-up mediated by the changes in pH.
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Di Paolo, Diana, Oshri Afanzar, Judith P. Armitage i Richard M. Berry. "Single-molecule imaging of electroporated dye-labelled CheY in live Escherichia coli". Philosophical Transactions of the Royal Society B: Biological Sciences 371, nr 1707 (5.11.2016): 20150492. http://dx.doi.org/10.1098/rstb.2015.0492.
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For the past two decades, the use of genetically fused fluorescent proteins (FPs) has greatly contributed to the study of chemotactic signalling in Escherichia coli including the activation of the response regulator protein CheY and its interaction with the flagellar motor. However, this approach suffers from a number of limitations, both biological and biophysical: for example, not all fusions are fully functional when fused to a bulky FP, which can have a similar molecular weight to its fused counterpart; they may interfere with the native interactions of the protein and the chromophores of FPs have low brightness and photostability and fast photobleaching rates. A recently developed technique for the electroporation of fluorescently labelled proteins in live bacteria has enabled us to bypass these limitations and study the in vivo behaviour of CheY at the single-molecule level. Here we show that purified CheY proteins labelled with organic dyes can be internalized into E. coli cells in controllable concentrations and imaged with video fluorescence microscopy. The use of this approach is illustrated by showing single CheY molecules diffusing within cells and interacting with the sensory clusters and the flagellar motors in real time. This article is part of the themed issue ‘The new bacteriology’.
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Peerzade, Saquib Ahmed M. A., Nadezda Makarova i Igor Sokolov. "Ultrabright Fluorescent Silica Nanoparticles for Multiplexed Detection". Nanomaterials 10, nr 5 (8.05.2020): 905. http://dx.doi.org/10.3390/nano10050905.
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Fluorescent tagging is a popular method in biomedical research. Using multiple taggants of different but resolvable fluorescent spectra simultaneously (multiplexing), it is possible to obtain more comprehensive and faster information about various biochemical reactions and diseases, for example, in the method of flow cytometry. Here we report on a first demonstration of the synthesis of ultrabright fluorescent silica nanoporous nanoparticles (Star-dots), which have a large number of complex fluorescence spectra suitable for multiplexed applications. The spectra are obtained via simple physical mixing of different commercially available fluorescent dyes in a synthesizing bath. The resulting particles contain dye molecules encapsulated inside of cylindrical nanochannels of the silica matrix. The distance between the dye molecules is sufficiently small to attain Forster resonance energy transfer (FRET) coupling within a portion of the encapsulated dye molecules. As a result, one can have particles of multiple spectra that can be excited with just one wavelength. We show this for the mixing of five, three, and two dyes. Furthermore, the dyes can be mixed inside of particles in different proportions. This brings another dimension in the complexity of the obtained spectra and makes the number of different resolvable spectra practically unlimited. We demonstrate that the spectra obtained by different mixing of just two dyes inside of each particle can be easily distinguished by using a linear decomposition method. As a practical example, the errors of demultiplexing are measured when sets of a hundred particles are used for tagging.
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Hanami, Takeshi, Tetsuya Tanabe, Takuya Hanashi, Mitsushiro Yamaguchi, Hidetaka Nakata, Yasumasa Mitani, Yasumasa Kimura i in. "Scanning single-molecule counting system for Eprobe with highly simple and effective approach". PLOS ONE 15, nr 12 (15.12.2020): e0243319. http://dx.doi.org/10.1371/journal.pone.0243319.
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Here, we report a rapid and ultra-sensitive detection technique for fluorescent molecules called scanning single molecular counting (SSMC). The method uses a fluorescence-based digital measurement system to count single molecules in a solution. In this technique, noise is reduced by conforming the signal shape to the intensity distribution of the excitation light via a circular scan of the confocal region. This simple technique allows the fluorescent molecules to freely diffuse into the solution through the confocal region and be counted one by one and does not require statistical analysis. Using this technique, 28 to 62 aM fluorescent dye was detected through measurement for 600 s. Furthermore, we achieved a good signal-to-noise ratio (S/N = 2326) under the condition of 100 pM target nucleic acid by only mixing a hybridization-sensitive fluorescent probe, called Eprobe, into the target oligonucleotide solution. Combination of SSMC and Eprobe provides a simple, rapid, amplification-free, and high-sensitive target nucleic acid detection system. This method is promising for future applications to detect particularly difficult to design primers for amplification as miRNAs and other short oligo nucleotide biomarkers by only hybridization with high sensitivity.
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Nakata, Eiji, Khongorzul Gerelbaatar, Futa Komatsubara i Takashi Morii. "Stimuli-Responsible SNARF Derivatives as a Latent Ratiometric Fluorescent Probe". Molecules 27, nr 21 (24.10.2022): 7181. http://dx.doi.org/10.3390/molecules27217181.
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Fluorescence imaging is a powerful technique for continuous observation of dynamic intracellular processes of living cells. Fluorescent probes bearing a fluorescence switching property associated with a specific recognition or reaction of target biomolecule, that is, stimuli-responsibility, are important for fluorescence imaging. Thus, fluorescent probes continue to be developed to support approaches with different design strategies. When compared with simple intensity-changing fluorescent probes, ratiometric fluorescent probes typically offer the advantage of less sensitivity to errors associated with probe concentration, photobleaching, and environmental effects. For intracellular usage, ratiometric fluorescent probes based on small molecules must be loaded into the cells. Thus, probes having intrinsic fluorescence may obscure a change in intracellular signal if the background fluorescence of the remaining extracellular probes is high. To overcome such disadvantages, it is necessary to minimize the extracellular background fluorescence of fluorescent probes. Here, the design strategy of the latent ratiometric fluorescent probe for wash-free ratiometric imaging using a xanthene dye seminapthorhodafluor (SNARF) as the scaffold of fluorophore is discussed.
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Bekkaoui, Faouzi, i David I. Dunstan. "Permeabilization of Piceaglauca protoplasts to macromolecules". Canadian Journal of Forest Research 19, nr 10 (1.10.1989): 1316–21. http://dx.doi.org/10.1139/x89-202.
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Chemical permeabilization (polyethylene glycol, molecular weight 3350) and electropermeabilization (electroporation) treatments were applied to white spruce protoplasts to determine their effectiveness for uptake of membrane impermeable macromolecules. The two techniques have been compared using the membrane impermeable fluorescent dye calcein (molecular weight 622). The effects of varying the polyethylene glycol concentration, or the capacitance and voltage, were tested. In both techniques, the viability of protoplasts decreased after treatment compared with the controls. However, electroporation (capacitance 25 μF; voltage 300 V, 750 V•cm−1) gave better-permeabilization results (55% protoplast viability with 96% of these being fluorescent protoplasts) than the best treatment with polyethylene glycol (20%) (30% protoplast viability with 15% being fluorescent protoplasts). An investigation was made with the dye fluorescein isothiocyanate dextrans at different average molecular weights: 4000, 70 000, and 150 000. The degree of internalization by electroporation of each of these molecules did not substantially differ, though they were all low compared with calcein, which is suggestive of a limitation in permeability. The protoplasts subjected to either polyethylene glycol or electroporation treatments gave rise to callus and proembryos.
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Pyle, Joseph R., i Jixin Chen. "Photobleaching of YOYO-1 in super-resolution single DNA fluorescence imaging". Beilstein Journal of Nanotechnology 8 (2.11.2017): 2296–306. http://dx.doi.org/10.3762/bjnano.8.229.
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Super-resolution imaging of single DNA molecules via point accumulation for imaging in nanoscale topography (PAINT) has great potential to visualize fine DNA structures with nanometer resolution. In a typical PAINT video acquisition, dye molecules (YOYO-1) in solution sparsely bind to the target surfaces (DNA) whose locations can be mathematically determined by fitting their fluorescent point spread function. Many YOYO-1 molecules intercalate into DNA and remain there during imaging, and most of them have to be temporarily or permanently fluorescently bleached, often stochastically, to allow for the visualization of a few fluorescent events per DNA per frame of the video. Thus, controlling the fluorescence on–off rate is important in PAINT. In this paper, we study the photobleaching of YOYO-1 and its correlation with the quality of the PAINT images. At a low excitation laser power density, the photobleaching of YOYO-1 is too slow and a minimum required power density was identified, which can be theoretically predicted with the proposed method in this report.
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Kreuzer, Karl-Anton, Alexander Bohn, Joachim Lupberger, Jerome Solassol, Philipp le Coutre i Christian Andreas Schmidt. "Simultaneous Absolute Quantification of Target and Control Templates by Real-Time Fluorescence Reverse Transcription-PCR Using 4-(4′-Dimethylaminophenylazo)benzoic Acid as a Dark Quencher Dye". Clinical Chemistry 47, nr 3 (1.03.2001): 486–90. http://dx.doi.org/10.1093/clinchem/47.3.486.
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Abstract Background: Despite the many advantages of real-time fluorescence reverse transcription-PCR (RT-PCR) as a quantitative analytical tool, simultaneous quantification of target and reference templates within one reaction has not been reported. We developed such an assay with an internal reference template. Methods: For quantification of target and reference sequences, we used two fluorescent probes in one reaction vessel on an ABI PRISM 7700 SDS instrument. Fluorescent probes were labeled with either 6-carboxy-fluorescein or hexachloro-6-carboxy-fluorescein as reporter dye and 4-(4′-dimethylaminophenylazo)benzoic acid (DABCYL) as a dark quencher fluorophore. To test the sensitivity and specificity of this assay, serial dilutions of reference and target templates were analyzed in one PCR reaction. In the presence of 10 β-actin molecules as control templates, 105 bcr/abl molecules were amplified, and 105 β-actin molecules were amplified in the presence of 10 bcr/abl copies. We also performed single and duplex measurements on samples from five patients with documented Philadelphia chromosome-positive chronic myelogenous leukemia disease courses (72 samples) and three with minor bcr/abl+ acute myelogenous leukemias (26 samples). Results: For M-bcr/abl duplex RT-PCR, the correlation coefficient (r) for starting template amounts and threshold cycle values was 0.99; for m-bcr/abl, r = 0.96, indicating a precise log-linear relation for 10–105 copies/100 ng of cDNA. In the same PCR reactions, r = 0.99 for β-actin (coamplified with M-bcr/abl or m-bcr/abl) for 103–107 copies/100 ng cDNA. The linear correlation coefficient for single and duplex measurements was 0.98 for M- and m-bcr/abl in patient samples. Conclusions: DABCYL can be used as dark quencher fluorophore in real-time fluorescence PCR. The duplex fluorescence RT-PCR assay for bcr/abl and β-actin transcripts allows monitoring of bcr/abl+ leukemias.
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Bielejewska, Natalia, Roland Stolarski i Danuta Bauman. "Characterization of Pure and Mixed Langmuir and Langmuir-Blodgett Films of Some Fluorescent Naphthalimide Dyes". Zeitschrift für Naturforschung A 64, nr 7-8 (1.08.2009): 492–502. http://dx.doi.org/10.1515/zna-2009-7-812.
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AbstractLangmuir and Langmuir-Blodgett (LB) films formed of some fluorescent dyes, derivatives of 4-aminonaphthalimide, and their binary mixtures with the liquid crystal 4-heptyl-4’-cyanobiphenyl (7CB) have been studied. Surface pressure versus mean molecular area isotherms for Langmuir films have given information about the alignment of molecules in a monomolecular layer at the air/water interface. The absorption and fluorescence spectra of LB films have revealed the occurrence of aggregates among dye molecules. In the ground electronic state some fraction of aggregates of J-type have appeared, while in the excited state the excimers have been created. The latter statement has been confirmed by additional absorption and fluorescence measurements performed for dyes dissolved in 7CB and placed in sandwich cells of 10 μm in thickness.
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Hayashi, Kota, Mamoru Tamura, Shiho Tokonami i Takuya Iida. "Quantitative fluorescence spectroscopy of living bacteria by optical condensation with a bubble-mimetic solid–liquid interface". AIP Advances 12, nr 12 (1.12.2022): 125214. http://dx.doi.org/10.1063/5.0104984.
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Microbial interactions are closely related to human health, and secreted signal molecules from bacteria determine the gene expression of bacteria following bacterial cell density and signal molecule density. However, the conventional quantitative analysis of the number of bacteria requires several days using standard cultivation methods, and the detection of molecules secreted via microbial interactions is difficult since they are in extremely small amounts. In this study, we performed local fluorescence spectroscopy to quantitatively evaluate the density of the assembly of dispersoids (fluorescent microparticles and bacteria) under optical condensation at a solid–liquid interface on our developed bubble-mimetic substrate, which exhibits extremely low thermal damage after a few minutes of laser irradiation. The obtained results showed that the fluorescence intensity spectrum was positively correlated with the concentration of dispersoids even when only several tens of assembled microparticles were observed. Furthermore, a calibration curve was obtained by plotting the integrated fluorescence intensity by integrating the fluorescence intensity spectrum over the observed wavelength, and the concentration of living bacteria was quantitatively analyzed. The clarified mechanism of local fluorescence spectroscopy under optical condensation will pave the way for rapid and precise analysis of bacteria and their secreted biomolecules labeled with fluorescent dye.
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Raduly, Monica Florentina, Valentin Raditoiu, Alina Raditoiu, Luminita Eugenia Wagner, Viorica Amariutei i Cristian Andi Nicolae. "Luminescent Hybrid Materials Based on Curcumin Derivatives Embedded in Palygorskite". Materiale Plastice 55, nr 1 (30.03.2018): 63–67. http://dx.doi.org/10.37358/mp.18.1.4964.
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The seven curcumin derivatives were deposited on palygorskite in order to obtain hybrid materials. The fluorescence emission spectra of the obtained materials show a decrease in fluorescence intensity relative to the respective dyes, due to the environments around the dyestuff molecules created in the host matrices. Absorption studies show the best adsorption on the inorganic matrix, for the compounds with the hydroxyl groups. Correlating fluorescence spectra of hybrid materials with the results for absorption spectra of the dyes adsorbtion on the surface of the clay lead to the conclusion that a high percentage of the adsorbed dye had the effect of fluorescence quenching. Thus, it was confirmed that the fluorescent properties of hybrid materials depend on the interactions established between the fluorescent dyestuff and the inorganic network.
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Ullah, Faiz, Sami Ullah, Muhammad Farhan Ali Khan, Muhammad Mustaqeem, Rizwan Nasir Paracha, Muhammad Fayyaz ur Rehman, Fariha Kanwal, Syed Shams ul Hassan i Simona Bungau. "Fluorescent and Phosphorescent Nitrogen-Containing Heterocycles and Crown Ethers: Biological and Pharmaceutical Applications". Molecules 27, nr 19 (6.10.2022): 6631. http://dx.doi.org/10.3390/molecules27196631.
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Fluorescent molecules absorb photons of specific wavelengths and emit a longer wavelength photon within nanoseconds. Recently, fluorescent materials have been widely used in the life and material sciences. Fluorescently labelled heterocyclic compounds are useful in bioanalytical applications, including in vivo imaging, high throughput screening, diagnostics, and light-emitting diodes. These compounds have various therapeutic properties, including antifungal, antitumor, antimalarial, anti-inflammatory, and analgesic activities. Different neutral fluorescent markers containing nitrogen heterocycles (quinolones, azafluoranthenes, pyrazoloquinolines, etc.) have several electrochemical, biological, and nonlinear optic applications. Photodynamic therapy (PDT), which destroys tumors and keeps normal tissues safe, works in the presence of molecular oxygen with light and a photosensitizing drugs (dye) to obtain a therapeutic effect. These compounds can potentially be effective templates for producing devices used in biological research. Blending crown compounds with fluorescent residues to create sensors has been frequently investigated. Florescent heterocyclic compounds (crown ether) increase metal solubility in non-aqueous fluids, broadening the application window. Fluorescent supramolecular polymers have widespread use in fluorescent materials, fluorescence probing, data storage, bio-imaging, drug administration, reproduction, biocatalysis, and cancer treatment. The employment of fluorophores, including organic chromophores and crown ethers, which have high selectivity, sensitivity, and stability constants, opens up new avenues for research. Fluorescent organic compounds are gaining importance in the biological world daily because of their diverse functionality with remarkable structural features and positive properties in the fields of medicine, photochemistry, and spectroscopy.
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Pronkin, Pavel G., i Alexander S. Tatikolov. "Photonics of Trimethine Cyanine Dyes as Probes for Biomolecules". Molecules 27, nr 19 (27.09.2022): 6367. http://dx.doi.org/10.3390/molecules27196367.
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Cyanine dyes are widely used as fluorescent probes in biophysics and medical biochemistry due to their unique photophysical and photochemical properties (their photonics). This review is focused on a subclass of the most widespread and studied cyanine dyes—trimethine cyanines, which can serve as potential probes for biomolecules. The works devoted to the study of the noncovalent interaction of trimethine cyanine dyes with biomolecules and changing the properties of these dyes upon the interaction are reviewed. In addition to the spectral-fluorescent properties, elementary photochemical properties of trimethine cyanines are considered, including: photoisomerization and back isomerization of the photoisomer, generation and decay of the triplet state, and its quenching by oxygen and other quenchers. The influence of DNA and other nucleic acids, proteins, and other biomolecules on these properties is covered. The interaction of a monomer dye molecule with a biomolecule usually leads to a fluorescence growth, damping of photoisomerization (if any), and an increase in intersystem crossing to the triplet state. Sometimes aggregation of dye molecules on biomolecules is observed. Quenching of the dye triplet state in a complex with biomolecules by molecular oxygen usually occurs with a rate constant much lower than the diffusion limit with allowance for the spin-statistical factor 1/9. The practical application of trimethine cyanines in biophysics and (medical) biochemistry is also considered. In conclusion, the prospects for further studies on the cyanine dye–biomolecule system and the development of new effective dye probes (including probes of a new type) for biomolecules are discussed.
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Yue, Yanfeng, Andrew J. Binder, Ruijing Song, Yuanjing Cui, Jihua Chen, Dale K. Hensley i Sheng Dai. "Encapsulation of large dye molecules in hierarchically superstructured metal–organic frameworks". Dalton Trans. 43, nr 48 (2014): 17893–98. http://dx.doi.org/10.1039/c4dt02516d.
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A perturbation assisted nanofusion technique to construct hierarchically superstructured MOFs was reported. In particular, the mesopores in the MOF structure enabled the confinement of large dye species, resulting in fluorescent dye@MOF composite materials.
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Surzhikova, Darya P., Lev A. Sukovatyi, Elena V. Nemtseva, Elena N. Esimbekova i Evgenia A. Slyusareva. "Functioning of a Fluorescein pH-Probe in Aqueous Media: Impact of Temperature and Viscosity". Micromachines 14, nr 7 (18.07.2023): 1442. http://dx.doi.org/10.3390/mi14071442.
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In this work, we considered the influence of viscogenic agents (glycerol, sucrose) as well as the temperature on the fluorescent characteristics of fluorescein at pH 6.5 in order to describe the acid-base status of local environment in terms of a spectrally detectable dianion-anion equilibrium. The protolytic equilibrium of fluorescein was found to depend on the solvent viscosity in a complex way. Whereas in the presence of sucrose the ratiometric signal of fluorescein (I488/I435) remains rather unchanged, the addition of glycerol (up to 40% w/w) results in the increase of the signal (up to 19%), that can be attributed to the different mechanisms of cosolvents effects on dye molecules in the ground state. Molecular dynamics of the dye in the presence of glycerol and sucrose revealed that the cosolvents preferentially interact with fluorescein monoanion and dianion, displacing water molecules from the local environment which in turn reduces the average number of the hydrogen bonds between xanthene ring of the dye and water molecules. The ratiometric signal demonstrates linear growth with the temperature in the range of 10–80 °C regardless of the presence of viscogenic agents. A linear correlation between the temperature sensitivity of the ratiometric signal and the change in the molar enthalpy of the proton dissociation reaction in buffer and viscous media was determined.
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Abrar, Shazia, Kazim Raza Naqvi, Sadia Javed, Shumaila Kiran i Tahsin Gulzar. "Synthesis of a Fluorescent Whitening Molecule and its Application to Wool Fibres". Current Organic Synthesis 16, nr 2 (26.03.2019): 314–18. http://dx.doi.org/10.2174/1570179416666190206141751.
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Aim and Objective: Reactive dye molecules are commonly employed to dye or modify colour characteristics of wool fibres. Yellowness of wool fibres poses a challenge and here, we report synthesis of a reactive fluorescent molecule and its application to wool fibres to reduce yellowness of the wool fibre and improve its colour features. Material and Methods: The new molecule was based upon 7-amino-4-methylcoumarin (AMC) and 2,4,6- trichloro-1,3,5-triazine (TZT). The synthesis involved a two-step chemical reaction, initiated by the nucleophilic substitution of a chloro group on the triazine ring with the hydroxyl group of 4-hydroxybenzenesulfonic acid. The substitution of 2nd chloro group at triazine ring with the amino group of 7-amino-4-methylcoumarin resulted in a novel molecule with a monofunctional reactive chloro group (AMC-MCT molecule). Results: The new molecule was applied to the wool fibres using exhaust dyeing method. This exhibited a high exhaustion value; however low fixation and total efficiency values were observed for the new molecule. The resultant wool fibres exhibited fluorescence which shows that aminocoumarin fluorophore retained its fluorescence when incorporated in the new molecule. An assessment of the molecule for yellowness index in a controlled exposure to UV radiation suggested an improvement in whiteness of wool fibre. Conclusion: A novel aminocoumarin based fluorescent whitening molecule 2 has been synthesised and applied to the wool fibres. The new molecule continued to exhibit fluorescence after its application to the wool fibres. These results will encourage researchers to explore further possibilities for reactive whitening agent for wool fibres.
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Kricka, Larry J., i Paolo Fortina. "Analytical Ancestry: “Firsts” in Fluorescent Labeling of Nucleosides, Nucleotides, and Nucleic Acids". Clinical Chemistry 55, nr 4 (1.04.2009): 670–83. http://dx.doi.org/10.1373/clinchem.2008.116152.
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Abstract Background: The inherent fluorescent properties of nucleosides, nucleotides, and nucleic acids are limited, and thus the need has arisen for fluorescent labeling of these molecules for a variety of analytical applications. Content: This review traces the analytical ancestry of fluorescent labeling of nucleosides, nucleotides, and nucleic acids, with an emphasis on the first to publish or patent. The scope of labeling includes (a) direct labeling by covalent labeling of nucleic acids with a fluorescent label or noncovalent binding or intercalation of a fluorescent dye to nucleic acids and (b) indirect labeling via covalent attachment of a secondary label to a nucleic acid, and then binding this to a fluorescently labeled ligand binder. An alternative indirect strategy involves binding of a nucleic acid to a nucleic acid binder molecule (e.g., antibody, antibiotic, histone, antibody, nuclease) that is labeled with a fluorophore. Fluorescent labels for nucleic acids include organic fluorescent dyes, metal chelates, carbon nanotubes, quantum dots, gold particles, and fluorescent minerals. Summary: Fluorescently labeled nucleosides, nucleotides, and nucleic acids are important types of reagents for biological assay methods and underpin current methods of chromosome analysis, gel staining, DNA sequencing and quantitative PCR. Although these methods use predominantly organic fluorophores, new types of particulate fluorophores in the form of nanoparticles, nanorods, and nanotubes may provide the basis of a new generation of fluorescent labels and nucleic acid detection methods.
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Hashim, Hairulazwan, Hisataka Maruyama, Yusuke Akita i Fumihito Arai. "Hydrogel Fluorescence Microsensor with Fluorescence Recovery for Prolonged Stable Temperature Measurements". Sensors 19, nr 23 (29.11.2019): 5247. http://dx.doi.org/10.3390/s19235247.
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This work describes a hydrogel fluorescence microsensor for prolonged stable temperature measurements. Temperature measurement using microsensors has the potential to provide information about cells, tissues, and the culture environment, with optical measurement using a fluorescent dye being a promising microsensing approach. However, it is challenging to achieve stable measurements over prolonged periods with conventional measurement methods based on the fluorescence intensity of fluorescent dye because the excited fluorescent dye molecules are bleached by the exposure to light. The decrease in fluorescence intensity induced by photobleaching causes measurement errors. In this work, a photobleaching compensation method based on the diffusion of fluorescent dye inside a hydrogel microsensor is proposed. The factors that influence compensation in the hydrogel microsensor system are the interval time between measurements, material, concentration of photo initiator, and the composition of the fluorescence microsensor. These factors were evaluated by comparing a polystyrene fluorescence microsensor and a hydrogel fluorescence microsensor, both with diameters of 20 µm. The hydrogel fluorescence microsensor made from 9% poly (ethylene glycol) diacrylate (PEGDA) 575 and 2% photo initiator showed excellent fluorescence intensity stability after exposure (standard deviation of difference from initial fluorescence after 100 measurement repetitions: within 1%). The effect of microsensor size on the stability of the fluorescence intensity was also evaluated. The hydrogel fluorescence microsensors, with sizes greater than the measurement area determined by the axial resolution of the confocal microscope, showed a small decrease in fluorescence intensity, within 3%, after 900 measurement repetitions. The temperature of deionized water in a microchamber was measured for 5400 s using both a thermopile and the hydrogel fluorescence microsensor. The results showed that the maximum error and standard deviation of error between these two sensors were 0.5 °C and 0.3 °C, respectively, confirming the effectiveness of the proposed method.
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Yan, Li, Yu Wang, Jinhua Li, Sergii Kalytchuk, Andrei S. Susha, Stephen V. Kershaw, Feng Yan, Andrey L. Rogach i Xianfeng Chen. "Highly luminescent covalently bonded layered double hydroxide–fluorescent dye nanohybrids". J. Mater. Chem. C 2, nr 22 (2014): 4490–94. http://dx.doi.org/10.1039/c3tc32483d.
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Šranková, Mária, Aleš Dvořák, Marek Martínek, Peter Šebej, Petr Klán, Libor Vítek i Lucie Muchová. "Antiproliferative and Cytotoxic Activities of Fluorescein—A Diagnostic Angiography Dye". International Journal of Molecular Sciences 23, nr 3 (28.01.2022): 1504. http://dx.doi.org/10.3390/ijms23031504.
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Fluorescein is a fluorescent dye used as a diagnostic tool in various fields of medicine. Although fluorescein itself possesses low toxicity, after photoactivation, it releases potentially toxic molecules, such as singlet oxygen (1O2) and, as we demonstrate in this work, also carbon monoxide (CO). As both of these molecules can affect physiological processes, the main aim of this study was to explore the potential biological impacts of fluorescein photochemistry. In our in vitro study in a human hepatoblastoma HepG2 cell line, we explored the possible effects on cell viability, cellular energy metabolism, and the cell cycle. We observed markedly lowered cell viability (≈30%, 75–2400 μM) upon irradiation of intracellular fluorescein and proved that this decrease in viability was dependent on the cellular oxygen concentration. We also detected a significantly decreased concentration of Krebs cycle metabolites (lactate and citrate < 30%; 2-hydroxyglutarate and 2-oxoglutarate < 10%) as well as cell cycle arrest (decrease in the G2 phase of 18%). These observations suggest that this photochemical reaction could have important biological consequences and may account for some adverse reactions observed in fluorescein-treated patients. Additionally, the biological activities of both 1O2 and CO might have considerable therapeutic potential, particularly in the treatment of cancer.
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Qin, Chuan Xiang, Ren Cheng Tang i Guo Qiang Chen. "Study on the Dyeing Properties of Hemicyanine Dyes in Acrylic Fabrics". Advanced Materials Research 175-176 (styczeń 2011): 587–92. http://dx.doi.org/10.4028/www.scientific.net/amr.175-176.587.
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In this paper, two hemicyanine dyes, DEASPI and DHEASPI-C1, were synthesized and used in acrylic fabrics as fluorescent dyes. The influence of the hydroxyl groups of dye molecules on the dyeing properties was analyzed, and the results showed that the exhaustion value and partition coefficient value decreased a lot when there were two hydroxyl groups attached to the end of dye molecule. The reflectance of the dyed acrylic fabrics with these two fluorescent dyes is higher than 100% in 600 - 700 nm. Moreover, the chromaticity of dyed acrylic fabric was calculated according to the EN-471 standard (2003).
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Ponyaev, Alexander I., i Jana S. Glukhova. "MOLECULAR ENGINEERING OF MECHANOFLUOROCHROME LUMINESCENT PROBES". Bulletin of the Saint Petersburg State Institute of Technology (Technical University) 59 (2021): 79–85. http://dx.doi.org/10.36807/1998-9849-2021-59-85-79-85.
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Luminescent materials – developed using appropriate molecular engineering – are capable of signaling about various irritants with high sensitivity. In particular, mechanofluorochrome materials show fluorescence emission that is sensitive to mechanical stimulation (pressure, shear, cracking, grinding). Mechanically sensitive compounds are attracting increasing interest and various molecules are synthesized that respond to mechanical stress by changing their fluorescent characteristics (emission wavelength, intensity, polarization, Stokes shift). For a deeper understanding of the relationship between the structure of the dye and its mechanofluorochrome properties, a review of compounds possessing this property is given in the work.
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Pillai, Sreenadh Sasidharan, Hiroshi Yukawa, Daisuke Onoshima, Vasudevanpillai Biju i Yoshinobu Baba. "Quantum Dot-Peptide Nanoassembly on Mesoporous Silica Nanoparticle for Biosensing". Nano Hybrids and Composites 19 (luty 2018): 55–72. http://dx.doi.org/10.4028/www.scientific.net/nhc.19.55.
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Quantum dots (QDs) are powerful luminescent probes for detecting single-molecules and imaging live cells. Despite several reports on bioimaging and biosensing applications of QDs, controlled and targeted detection of biomolecules using quantum dots is an ongoing challenge. When a QD is conjugated with an ideal chromophore, which can be a fluorescent or a non-fluorescent dye molecule, QD luminescence can be quenched by Förster resonance energy transfer (FRET) to the quencher dye. However, the photoluminescence of QD can be recovered upon on-demand release of the quencher. Our study focuses on quenching of QD photoluminescence after conjugation with a non-fluorescent dye molecule, black hole quencher 1 (BHQ-1), intermediated with a molecular sensing target peptide GPLG↓VRGK. Based on steady-state and time-resolved photoluminescence measurements of QD and the QD-peptide-BHQ-1 sensor assemblies, we attribute the quenching of photoluminescence intensity and lifetime to FRET from the QD to BHQ-1molecules. Here the intermediate peptide GPLG↓VRGK can be cleaved by matrix metalloproteinase-2 (MMP-2), an enzyme that is upregulated in cancer cells extra cellular matrix (ECM), at its Gly and Val region shown by the down headed arrow. Here the QD-pep-BHQ-1 conjugate detected the MMP-2 presence at the extra cellular matrix of H1299 cancer cells. Further the QD-pep-BHQ-1 molecules were conjugated at the surface of a mesoporous silica nanoparticle (MSN) scaffold to localize maximum target peptide in a nanospace volume for the future αvβ3 integrin receptor targeted detection of MMP-2. The luminescence quenching of MSN-QD-pep-BHQ-1 conjugates were analyzed with time resolved photoluminescence measurement.
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Fu, Bing, Jessica D. Flynn, Benjamin P. Isaacoff, David J. Rowland i Julie S. Biteen. "Super-Resolving the Distance-Dependent Plasmon-Enhanced Fluorescence of Single Dye and Fluorescent Protein Molecules". Journal of Physical Chemistry C 119, nr 33 (6.08.2015): 19350–58. http://dx.doi.org/10.1021/acs.jpcc.5b05154.
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Semenov, Alexey N., Daniil A. Gvozdev, Anastasia M. Moysenovich, Dmitry V. Zlenko, Evgenia Yu Parshina, Adil A. Baizhumanov, Gleb S. Budylin i Eugene G. Maksimov. "Probing Red Blood Cell Membrane Microviscosity Using Fluorescence Anisotropy Decay Curves of the Lipophilic Dye PKH26". International Journal of Molecular Sciences 23, nr 24 (12.12.2022): 15767. http://dx.doi.org/10.3390/ijms232415767.
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Red blood cell (RBC) aggregation and deformation are governed by the molecular processes occurring on the membrane. Since several social important diseases are accompanied by alterations in RBC aggregation and deformability, it is important to develop a diagnostic parameter of RBC membrane structural integrity and stability. In this work, we propose membrane microviscosity assessed by time-resolved fluorescence anisotropy of the lipophilic PKH26 fluorescent probe as a diagnostic parameter. We measured the fluorescence decay curves of the PKH26 probe in the RBC membrane to establish the optimal parameters of the developed fluorescence assay. We observed a complex biphasic profile of the fluorescence anisotropy decay characterized by two correlation times corresponding to the rotational diffusion of free PKH26, and membrane-bounded molecules of the probe. The developed assay allowed us to estimate membrane microviscosity in the range of 100–500 cP depending on the temperature, which paves the way for assessing RBC membrane properties in clinical applications as predictors of blood microrheological abnormalities.
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Svechkarev, Denis, i Aaron M. Mohs. "Organic Fluorescent Dye-based Nanomaterials: Advances in the Rational Design for Imaging and Sensing Applications". Current Medicinal Chemistry 26, nr 21 (19.09.2019): 4042–64. http://dx.doi.org/10.2174/0929867325666180226111716.
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Self-assembled fluorescent nanomaterials based on small-molecule organic dyes are gaining increasing popularity in imaging and sensing applications over the past decade. This is primarily due to their ability to combine spectral properties tunability and biocompatibility of small molecule organic fluorophores with brightness, chemical and colloidal stability of inorganic materials. Such a unique combination of features comes with rich versatility of dye-based nanomaterials: from aggregates of small molecules to sophisticated core-shell nanoarchitectures involving hyperbranched polymers. Along with the ongoing discovery of new materials and better ways of their synthesis, it is very important to continue systematic studies of fundamental factors that regulate the key properties of fluorescent nanomaterials: their size, polydispersity, colloidal stability, chemical stability, absorption and emission maxima, biocompatibility, and interactions with biological interfaces. In this review, we focus on the systematic description of various types of organic fluorescent nanomaterials, approaches to their synthesis, and ways to optimize and control their characteristics. The discussion is built on examples from reports on recent advances in the design and applications of such materials. Conclusions made from this analysis allow a perspective on future development of fluorescent nanomaterials design for biomedical and related applications.
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Yoon, Suhyun, i David Keller. "Developing Sensors of Chemical Warfare Agent Simulants with Fluorescent Dye Molecules". Biophysical Journal 110, nr 3 (luty 2016): 509a. http://dx.doi.org/10.1016/j.bpj.2015.11.2718.
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Alkhursani, Sheikha A., Mohamed Mohamady Ghobashy i Mohamed Madani. "Radiation Synthesis of Organostarch as Fluorescence Label". Asian Journal of Chemistry 32, nr 7 (2020): 1799–805. http://dx.doi.org/10.14233/ajchem.2020.22593.
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Fluorescence label preparation, being the core of sensing and imaging, is the most interesting aspect of label technology. Using the gamma irradiation technique, a facial method is proposed to prepare organostarch consisting of polyaniline and starch. Polyaniline was introduced into starch molecules to form an inclusion complex between V-type starch and aniline monomer. The inclusion complex thus formed consisted of starch-aniline crosslink caused by gamma irradiation through organostarch crosslinks. Thus, organostarch develops fluorescence property at 470 nm possibly through the interaction of aniline and starch, which are both fluorophores. A comparative analysis of variations is performed in common fluorescent labels of starch and organostarch based on their physico-chemical properties. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectrometry were utilized to confirm the inclusion of polyaniline into starch molecules. Furthermore, using a fluorescence microscope, the positive implementation of fluorescent organostarch was verified. Fluorescent organostarch can be synthesized through this simple method and can be widely used for developing biomarkers and biosensors in food and biomedical industries. Organostarch produces florescence under mild conditions even without complicated preparations, such as additives for labelling with dye fluorescence. The intensity of fluorescence of organostarch was 17,000 times that of natural starch.
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Lwin, Thinzar M., Michael A. Turner, Hiroto Nishino, Siamak Amirfakhri, Sophie Hernot, Robert M. Hoffman i Michael Bouvet. "Fluorescent Anti-CEA Nanobody for Rapid Tumor-Targeting and Imaging in Mouse Models of Pancreatic Cancer". Biomolecules 12, nr 5 (16.05.2022): 711. http://dx.doi.org/10.3390/biom12050711.
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Tumor-specific targeting with fluorescent probes can enhance contrast for identification of cancer during surgical resection and visualize otherwise invisible tumor margins. Nanobodies are the smallest naturally-occurring antigen-binding molecules with rapid pharmacokinetics. The present work demonstrates the efficacy of a fluorescent anti-CEA nanobody conjugated to an IR800 dye to target and label patient derived pancreatic cancer xenografts. After intravenous administration, the probe rapidly localized to the pancreatic cancer tumors within an hour and had a tumor-to-background ratio of 2.0 by 3 h. The fluorescence signal was durable over a prolonged period of time. With the rapid kinetics afforded by fluorescent nanobodies, both targeting and imaging can be performed on the same day as surgery.