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Heteroatom-substituted rhodamine dyes: Structure and spectroscopic properties
摘要： Rhodamine is one class of most popular dyes used in fluorescence imaging due to the outstanding photoproperties including high brightness and photostability. In recent years, replacement the xanthene oxygen with other elements, especially silicon, has attracted great attentions in the development of new rhodamine derivatives. This review summarized the structures and photophysical properties of heteroatom-substituted rhodamines. We hope this review can help to understand the structure-property relationships of rhodamine dyes and then elucidate the way to create derivatives with improved photoproperties.
关键词： Heteroatom,Optical properties,Si-rhodamine,Rhodamine,Fluorescent dyes
更新于2025-09-23 15:23:52
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G-quadruplex specific dye-based ratiometric FRET aptasensor for robust and ultrafast detection of toxin
摘要： G-quadruplex specific dyes are powerful tools for probing nucleic acid structures. Among nucleic acids, aptamers are of great interest, and widely exploited to construct versatile bioassays. Herein, based on G-quadruplex selective dye, thioflavin T (ThT), for probing the intrinsic structure of aptamers, we proposed a ratiometric fluorescence resonance energy transfer (FRET) aptasensor enabling robust and ultrafast detection of toxin. The binding of target ochratoxin A (OTA) would destruct the G-quadruplex structure of aptamer. It would lead to the detachment of ThT dye from aptamer which diminished the FRET effect between ThT and terminal-labeled dye, thus allowing quantification of OTA via FRET signals. The FRET aptasensor would confer an enhancement of 76.9% of signal to background ratio compared to the ThT-based non-FRET aptasensor. Remarkably, the FRET mechanism would eliminate the signal fluctuation resulted from varied probe concentration, thus benefiting the robustness of the assay. The aptasensor could achieve a detection of limit of 0.38 ng/mL for OTA detection. And the detection of OTA could be finished within 30 s. Besides, the assay was successful in analyzing OTA in coffee and oat samples with recoveries rate of 93.93%–107.59%. Therefore, G-quadruplex specific dye-based probing and FRET method would be a compelling design strategy for aptasensor, and may facilitate their practical application in food safety and environmental screening.
关键词： Fluorescence resonance energy transfer,G-quadruplex specific dyes,Homogeneous analysis,Toxin,Thioflavin T,Aptamer
更新于2025-09-23 15:23:52
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Artificial neural network modeling of a pilot plant jet-mixing UV/hydrogen peroxide wastewater treatment system
摘要： This study deals with the modeling and simulation of an efficient pilot plant photo-chemical wastewater treatment reactor. Treatment of an azo dye (i.e. direct red 23) was performed using a UV/H2O2 process in a jet mixing photo-reactor with 10-L volume. To model the reactor and simulate the treatment process, six important, influential physical and chemical factors such as nozzle angle (hN), nozzle diameter (dN), flow-rate (Q), irradiation time (t), H2O2 initial concentration ([H2O2]0), and pH, were taken into account. In this regard, artificial neural networks (ANNs) were employed as a powerful modeling methodology. Six different ANN architectures were constructed and most appropriate numbers for hidden neuron and learning iteration were determined based on minimization of the mean square error (MSE) function related to the testing data sets. Furthermore, simulation of the reactor efficiency, as well as sensitivity analysis, was performed via the cross-validation outputs. It was found that a three-layered feed-forward ANN composes ten hidden neurons, calibrated at 100th iteration using “trainlm” as learning algorithm and “tansig” and “purelin” as transfer functions in the hidden and output layers can model the process as the best case. The order of importance for variation of the key factors were indicated as [H2O2]0 > t > pH > Q > hN > dN.
关键词： dyes,simulation,wastewater treatment,Advance oxidation process,neural networks,photodegradation,batch reactor
更新于2025-09-23 15:23:52
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Ultraviolet-light-assisted heterogeneous Fenton reaction of Ag-Fe3O4/graphene composites for the degradation of organic dyes
摘要： In this study, Fe3O4/graphene and Ag-Fe3O4/graphene composites with varying content of graphene and Ag were prepared and used as a heterogeneous Fenton catalyst for the degradation of MO and MB under UV-light irradiation. The physicochemical properties of the obtained catalysts were used for the Fenton reaction. In addition, the effects of graphene and Ag content, pH, H2O2 concentration, catalyst loading, and initial MO and MB concentrations on the degradation by the UV-Fenton process were evaluated. Results revealed that the highest removal efficiency of MO and MB is achieved at graphene and Ag concentrations of 10 and 25 wt%, respectively. Furthermore, Ag-Fe3O4/graphene composites were used to assess the degradation of a mixture of MO and MB and other anionic and cationic dyes. Results revealed that Ag-Fe3O4/graphene composites can be used as a broad-spectrum catalyst with good efficiency for the removal of several dye contaminants in water. Moreover, the effect of the addition of ascorbic acid (AA) on dye degradation was investigated. AA accelerated the degradation of organic dyes compared to that without AA. The obtained results revealed that Ag-Fe3O4/graphene composites exhibit stable catalytic activity and reusability after four successive runs.
关键词： Heterogeneous Fenton reaction,Organic dyes,Ag/Fe3O4/graphene
更新于2025-09-23 15:23:52
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Imaging extracellular vesicles: current and emerging methods
摘要： Extracellular vesicles (EVs) are lipid bilayer-enclosed nanoparticles released by cells. They range from 30 nm to several micrometers in diameter, and ferry biological cargos such as proteins, lipids, RNAs and DNAs for local and distant intercellular communications. EVs have since been found to play a role in development, as well as in diseases including cancers. To elucidate the roles of EVs, researchers have established different methods to visualize and study their spatiotemporal properties. However, since EV are nanometer-sized, imaging them demands a full understanding of each labeling strategy to ensure accurate monitoring. This review covers current and emerging strategies for EV imaging for prospective studies.
关键词： Bioluminescence,MRI,Microvesicles,SPECT,Biodistribution,Imaging,Extracellular vesicles,Fluorescence,Dyes,exosomes
更新于2025-09-23 15:23:52
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Chemometrics-assisted determination of Sudan dyes using zinc oxide nanoparticle-based electrochemical sensor
摘要： Multivariate curve resolution-alternating least squares (MCR-ALS) assisted with electrochemical techniques was applied for simultaneous determination of Sudan II and III at a surface of zinc oxide nanoparticles (ZnONPs) modified carbon paste electrode. Characterization of the ZnONPs and the nanostructured modified electrode was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. Response surface methodology using central composite rotatable design was employed to design of experiments and achieving to optimum values of variables. For simultaneous determination of Sudan II and III, electrochemical second order data were obtained by changing of pulse height in differential pulse voltammetry technique. MCR-ALS was performed on the data to obtain the decomposition peaks of analytes. Then, the detection limits were obtained 1.87 and 2.62 nM for Sudan II and III, respectively. Finally, this method used for the analysis of the two analytes in real samples.
关键词： ZnO nanoparticles,Differential pulse voltammetry,MCR-ALS,Sudan dyes,Second order data,Response surface methodology
更新于2025-09-23 15:22:29
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Molecular and excited state properties of photostable anthraquinone blue dyes for hydrophobic fibers
摘要： Synthetic dyes having high photostability on hydrophobic fibers such as poly(ethylene terephthalate) (PET) are of interest for use on textile substrates for outdoor applications. While much is known about photostable dyes developed for PET in the 1980s, owing to their viability for use in automobile interiors, little has been published on currently viable photostable disperse dyes. As part of an effort to help fill this void and to facilitate future photostable disperse dye design, the present study involved the use of experimental measurements and modelling studies to help characterize the molecular structures of commercially viable dyes for producing photostable colors on PET fibers, beginning with a pair of blue dyes. With the aid of HR-MS, 500 MHz 1H NMR, and X-ray crystallography, it was established that the two dyes are structural isomers having 1,5-(OH)2-anthraquinone (AQ) and 1,8-(OH)2-AQ base structures. It is proposed that the photostability of these dyes arises from the presence of multiple OH/NH groups ortho to the AQ C]O groups which enables them to dissipate excited state energy through intramolecular proton transfer. Further, using DFT-based molecular modelling studies, it was shown that the dye having the 1,5-(OH)2-AQ base structure has a lower ESOP than the isomeric dye having the 1,8-(OH)2-AQ base structure. Similarly, results from calculating Frontier HOMO and LUMO isosurfaces indicated that the LUMO lobes of the latter dye are larger, suggesting that this dye undergoes excitation faster than the 1,5-(OH)2-AQ isomer.
关键词： Molecular modelling,Anthraquinone disperse dyes,X-ray crystallography,Intramolecular H-bonding,Structural analysis
更新于2025-09-23 15:22:29
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Continuous In Vivo Monitoring of the Oxygen Concentration in Tissues
摘要： The kinetics of delayed fluorescence and phosphorescence of xanthene dyes in mouse tissues under the pulse-periodic excitation of molecules was studied in vivo and in vitro. The advantages of continuous monitoring of oxygen content in tissues by the kinetics of delayed fluorescence caused by singlet–triplet annihilation of singlet oxygen with triplet excitation of fluorophore are demonstrated. A method is proposed for determining the time of recovery of the concentration of oxygen consumed in tissues in vivo and in vitro during photodynamic processes.
关键词： delayed luminescence,singlet oxygen,tissues,xanthene dyes
更新于2025-09-23 15:22:29
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Influence of Titanium Dioxide Preparation Method on Photocatalytic Degradation of Organic Dyes
摘要： Titanium catalysts (TiO2) were synthesized by three different methods. Their photocatalytic activity was validated through photodegradation of Reactive Red 45 (RR45) azo dye and Acid Blue 25 (AB25) anthraquinone dye in an aqueous solution under UV irradiation. TiO2 photocatalysts were characterized by FTIR, XRD and SEM. Photosensitivity and TiO2 activity range were characterized by UV/Vis spectroscopy. Photocatalytic validation has been made by way of determining the degree of RR45 and AB25 removal. TOC was determined as a measure of the mineralization of RR45 and AB25 by photocatalysis. The stability of TiO2 catalysts and a possibility of using them in consecutive photocatalysis cycles have also been studied. The results show that the photocatalytic efficiency depends on the crystal structure of TiO2. The size of crystallites depends on synthesis conditions. From the results of photocatalytic efficiency it is concluded that the chemical interaction between a catalyst and a dye strongly depends on the dye chemical structure.
关键词： organic dyes,wastewater treatment,photocatalysis,titanium dioxide
更新于2025-09-23 15:22:29
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Aggregation-Induced Absorption Enhancement for Deep Near-Infrared II Photoacoustic Imaging of Brain Gliomas In Vivo
摘要： The delineation of brain gliomas margins still poses challenges to precise imaging and targeted therapy, mainly due to strong light attenuation of the skull and high background interference. With deep penetration and high sensitivity, photoacoustic (PA) imaging (PAI) in the second near-infrared (NIR II) window holds great potential for brain gliomas imaging. Herein, mesoionic dye A1094 encapsulated in Arg-Gly-Asp-modified hepatitis B virus core protein (RGD-HBc) is designed and synthesized for effective NIR II PAI of brain gliomas. An aggregation-induced absorption enhancement mechanism is discovered in vitro and in vivo. It is also demonstrated that A1094@RGD-HBc, with an enhanced absorption in the NIR II window, displays ninefold PA signal amplification in vivo, allowing for precise PAI of the brain gliomas at a depth up to 5.9 mm. In addition, with the application of abovementioned agent, high-resolution PAI and ultrasensitive single photon emission computed tomography images of brain gliomas are acquired with accurate co-localization. Collectively, the results suggest great promise of A1094@RGD-HBc for diagnostic imaging and precise delineation of brain gliomas in clinical applications.
关键词： mesoionic dyes,brain gliomas,aggregation-induced absorption enhancement,second near-infrared window,deep photoacoustic imaging
更新于2025-09-23 15:22:29