Simple substituents make big differences in photophysical performances of 2,1,3-benzothiadizole-conjugated spiropyrans

Developing multifunctional spiropyran dyes is of particular importance in diverse applications.In the present study,we synthesized two 2,1,3-benzothiadiazole-conjugated spiropyrans(BT-SP-NO2and BTSP-NMe2)with distinct substituents.These donor-acceptor-structured spiropyrans exhibited typical twisted intramolecular charge transfer features and strong emissions in low-polarity solvents with fluorescence quantum yields(QYs)of up to 90.7%.Like traditional spiropyrans,the electron-acceptor-substituted BT-SP-NO2exhibited excellent photochromic behavior under multiple alternating UV—Vis irradiation,while the electron-donor-substituted BT-SP-NMe2was an acidochromic dye.In addition,the substituent groups distinctly affected the packing modes of these spiropyrans in the solid state.BTSP-NMe2showed a much stronger solid-state emission(QY of 59.0%)than BT-SP-NO2.Moreover,these two dyes were utilized as biocompatible probes for the specific light-up imaging of lipid droplets.

Monitoring Xylem Transport in the Stem of Lilium lancifolium Using Fluorescent Dye 5(6)-Carboxyfluorescein Diacetate

The xylem undergoes physiological changes in response to various environmental conditions during the process of plant growth.To understand these physiological changes,it is extremely important to observe the transport of xylem.In this study,the distribution and structure of vascular bundle in Lilium lancifolium were observed using the method of semithin section.Methods for introducing a fluorescent tracer into the xylem of the stems were evaluated.Then,the transport rule of 5(6)-Carboxyfluorescein diacetate(CFDA)in the xylem of the stem of L.lancifolium was studied by fluorescence dye in live cells tracer technology.The results showed that the vascular bundles of L.lancifolium were scattered in the basic tissue,the peripheral vascular bundles were smaller and densely distributed,and the closer to the center,the larger the volume of vascular bundles and the more sparsely distributed.The vascular bundles of L.lancifolium are limited external tenacity vascular bundles,which are composed of phloem and xylem.The most suitable method for CFDA labeling the xylem of isolated stem segments of L.lancifolium was solution soaking for 24 h.The running speed of CF in the isolated stem was 0.3 cm/h,which was consistent with the running speed of the material in the field.CF could be transported between the xylem and parenchyma cells,indicating that the material transport in the xylem could be through the symplastic pathway.The above results laid a foundation for the study of the xylem transport mechanism and the xylem pathogen disease of lily.

Synthesis and Fluorescence Spectra of Triazolylcoumarin Fluorescent Dyes

Much attention is devoted to fluorescent dyes especially those with potential in versatile applications.Reactions under "click" conditions between nonfluorescent 3-azidocoumarins and terminal alkynes produced 3-(1,2,3-triazol-1-yl)coumarins,a novel type of fluorescent dyes with intense fluorescence.The structures of the new coumarins were characterized by 1H NMR,MS,and IR spectra.Fluorescence spectra measurement demonstrated excellent fluorescence performance of the triazolylcoumarins and this click reaction is a promising candidate for bioconjugation and bioimaging applications since both azide and alkynes are quite inert to biological systems.

Effects of Taxotere on invasive potential and multidrug resistance phenotype in pancreatic carcinoma cell line SUIT-2

INTRODUCTIONDevelopment of drug-resistance to chemotherapyand subsequent metastasis of tumor are primarilyresponsible for treatment failure and the death fromcancer. There have been many previous studies onthe relationship between expression of multidrugresistance (MDR) phenotype P-glycoprotein (P-gp)and the malignant properties of tumors, but theresults are often conflicting[1-8]. The difference intumor types or MDR phenotype induced by specificagents might account for this discrepancy. Taxotere(TXT), a member of the family of taxanes, hasantitumor activity through its effect of promotingthe polymerization of tubulin[9,10].

Synthesis and application of rhodamine-based fluorescent probe dyes with spacer linker arm

When rhodamine-based fluorescent probe dyes are used to track target molecules they always perturb the behavior of target molecules because of steric hindrance effect. In order to minimize potential steric problems, a kind of rhodamine-based fluorescent probe dye with spacer linker arm was designed and synthesized and its application in immunofluorescence histochemistry was investigated.

Novel Water Soluble Fluorescent Trimethine Indocyanines Containing N-ρ-Carboxybenzyl Group

Two fluorescent indocyanine dyes containing at least one p-carboxybenzyl group on the nitrogen atoms in the heterocyclic rings were designed and synthesized. Their absorption maxima were 549 nm and 551 nm in water respectively. They had good water solubility and photostability.

Synthesis of New Near-infrared Fluorescent Dyes

A new near-infrared fluorescent dye, 9-N-(2-hydroxyethyl)-N-methylamino-6-carbethoxy-5H-benzo[a]phenoxazin-5-one 1, was prepared from the reaction of N-(2-hydroxyethyl)-N-methyl-4-nitrosoaniline hydrochloride and ethyl 1,3-dihydroxynaphthoate. Five more fluorescent compounds were synthesized by the reaction of the resulting dye 1 with appropriate amino acid or carboxylic acids.

Enhancement of electroluminescent properties of organic optoelectronic integrated device by doping phosphorescent dye

Organic optoelectronic integrated devices（OIDs） with ultraviolet（UV） photodetectivity and different color emitting were constructed by using a thermally activated delayed fluorescence（TADF） material 4, 5-bis（carbazol-9-yl）-1, 2-dicyanobenzene（2 CzPN） as host. The OIDs doping with typical red phosphorescent dye [tris（1-phenylisoquinoline）iridium（Ⅲ）, Ir（piq）3], orange phosphorescent dye {bis[2-（4-tertbutylphenyl）benzothiazolato-N,C-（2＇）]iridium（acetylacetonate）,（tbt）2 Ir（acac）}, and blue phosphorescent dye [bis（2, 4-di-fluorophenylpyridinato）-tetrakis（1-pyrazolyl）borate iridium（Ⅲ）, FIr6] were investigated and compared. The（tbt）2 Ir（acac）-doped orange device showed better performance than those of red and blue devices, which was ascribed to more effective energy transfer. Meanwhile, at a low dopant concentration of 3 wt.%, the（tbt）2 Ir（acac）-doped OIDs showed the maximum luminance, current efficiency, power efficiency of 70786 cd/m^2, 39.55 cd/A, and 23.92 lm/W, respectively, and a decent detectivity of 1.07 × 10^11 Jones at a bias of -2 V under the UV-350 nm illumination. This work may arouse widespread interest in constructing high efficiency and luminance OIDs based on doping phosphorescent dye.

SUPPRESSION OF SIDELOBES IN SINGLE-PHOTON 4PI CONFOCAL MICROSCOPY BY FORSTER RESONANT ENERGY TRANSFER

Recently,we theoretically demonstrate that utilization of silica nanobeads co-doped with Cy3 and Cy5 molecules instead of single dye molecules asfluorescent labels can enable optical resolutions far beyond the diffraction-limit.Here,we show that by combining the 4Pi microscopy and the novelfluorescent label,it is possible to completely suppress the sidelobes in 4Pi focal spot and significantly enhance the optical resolution in the axial direction.

Syntheses of Some Organic Fluorescent Dyes for Security Tickers

Five organic fluorescence dyes were synthesized by two- or three-step reactions. These synthetic methods have an advantage of the simple processes, low costs and high yields. The compositions of the five compounds are characterized by IR, 1H NMR, elemental analyses and fluorescence spectroscopies. The quantum yields of fluorescence were measured.

Green Light-Emitting Organic Electroluminescent Device with a New Fluorescent Dye Dispersed in Poly(N-vinylcarbazole) Emitter Layer

Double-layer organic electroluminescent devices have been constructed. A new fluorescent dye, 9,10-bis(phenylethynyl)anthracence, was chosen as the dopant which was molecularly dispersed in the polymer film, and green light was observed from the device with luminance of 130cd/m(2) at 17V.

Chromaticity Characteristics of Fluorescent Dyes in Cloth

Chromaticity characteristics of several fluorescent dyes in cloth were studied in terms of chromaticity diagram. The dominant wavelength and color purity of the samples were calculated and chromaticity diagrams were drawn to provide countermeasures with which the perceptual color attributes such as hue and saturation are correlated.

Multicolor Anti-counterfeiting Strategy and Synchronous High Capacity Storage Based on Acidochromic Organic Fluorescent Materials

Comprehensive Summary Many industries are plagued by economic losses and product failures caused by counterfeit goods.Therefore,advanced anti-counterfeiting techniques are continuously needed.In this study,we constructed a series of acid-base sensitive cyclic chalcone dyes A—F by modifying different electron-donating groups.Differences in acid sensitivity of different structures are well rationalised by NMR and theoretical calculations.Aniline is difficult to protonate than fatty amines,so there is a difference in fluorescence.Hiding and anti-counterfeiting of information is achieved by this phenomenon.Powder X and Y are the anti-counterfeit fluorescent powder containing montmorillonite and cyclic chalcone,which have orange fluorescence and the very similar appearance.However,under the influence of acid the Powder X containing triphenylamine modified cyclic chalcone shows red shifted fluorescence and Powder Y containing morpholino and diethylamino groups modified cyclic chalcone shows blue shifted fluorescence.Therefore,the anti-counterfeiting strategy based on cyclic chalcone is not only limited to UV-irradiated fluorescence development,but also has more colorization and pattern variations with the aid of acid developer.Data encryption and decryption of numbers,English alphabets and Chinese characters have been realized using A—F,which have great potential for practical applications.

What have we known so far for fluorescence staining and quantification of microplastics:A tutorial review

Understanding the fate and toxicity of microplastics(MPs,<5 mm plastic particles)is limited by quantification methods.This paper summarizes the methods in use and presents new ones.First,sampling and pretreatment processes ofMPs,including sample collection,digestion,density separation,and quality control are reviewed.Then the promising and convenient staining procedures and quantification methods for MPs using fluorescence dyes are reviewed.The factors that influence the staining of MPs,including their physicochemical properties,are summarized to provide an optimal operation procedure.In general,the digestion step is crucial to eliminate natural organic matter(NOM)to avoid interference in quantification.Chloroform was reported to be the most appropriate solvent,and 10–20μg/mL are recommended as optimal dye concentrations.In addition,a heating and cooling procedure is recommended to maintain the fluorescence intensity of MPs for two months.After staining,a fluorescence microscope is usually used to characterize the morphology,mass,or number of MPs,but compositional analysis cannot be determined with it.These fluorescence staining methods have been implemented to study MP abundance,transport,and toxicity and have been combined with other chemical characterization techniques,such as Fourier transform infrared spectroscopy and Raman spectroscopy.More studies are needed to focus on the synthesis of novel dyes to avoid NOM’s interference.They need to be combined with other spectroscopic techniques to characterize plastic composition and to develop image-analysis methods.The stability of stained MPs needs to be improved.

Better understanding of the activated sludge process combining fluorescence-based methods and flow cytometry:A case study

This study aims to demonstrate the validity of fluorescence-based methods,together with flow cytometry,as a complementary tool to conventional physicochemical analyses carried out in wastewater treatment plants(WWTPs),for the control of the currently largely unknown activated sludge process.Staining with SYTO 9,propidium iodide and 5-(and 6)-carboxy-2’,7’-difluorodihydrofluorescein diacetate(carboxy-H2 DFFDA)was used for cell viability and oxidative stress monitoring of the bacterial population forming the activated sludge of a WWTP.Throughout the period of research,several unstable periods were detected,where the non-viable bacteria exceeded the 75%of the total bacterial population in the activated sludge,but only in one case the cells with oxidative stress grew to 9%,exceeding the typical values of2%-5%of this plant.These periods coincided in two cases with high values of total suspended solids(SST)and chemical oxygen demand(COD)in the effluent,and with an excess of ammonia in other case.A correlation between flow cytometric and physicochemical data was found,which enabled to clarify the possible origin of each case of instability in the biological system.This experience supports the application of bacterial fluorescence staining,together with flow cytometric analysis,as a simple,rapid and reliable tool for the control and better understanding of the bacteria dynamics in a biological wastewater treatment process.

Immobilization of GO_(X) on PEG/fluoresence functionalized nanographene oxide to describe fluctuation of glucose level

Enzyme,produced and worked in all living things,could work as macromolecular biological catalysts in diverse biochemical processes with particular specificity,like glucose oxidase(GOX).The efficient use of enzyme properties has great importance in pharmaceutics and therapeutics.In this work,we could fabricate naive and effective electrochemical biosensors in the determination of glucose levels via utilizing GOX.Graphene oxide,as a water-soluble derivative of graphene,has shown great promise in a variety of biomedical applications including biosensors.Thus,we established a new-type special platform for GOX immobilization to perform its prosperities,in which nanographene oxide(nGO)was employed as an ideal base and poly(ethylene glycol)(PEG)was conjugated on the edge of nGO sheets to enhance its biocompatibility.Additionally,preferable functional dyes(Rhodamine B/fluorescein isothiocyanate)were also introduced to the platform.Enzyme-nanocomposites were then provided by locating GOX on the platform,i.e.,GOX@nGO-PEG-RhB and GOX@nGO-PEG-FITC.The microstructure and composite of platforms and enzyme-nanocomposites were confirmed by diverse characterizations.Finally,on account of corresponding cyclic voltammetric and typical ready-state amperometric curves,it was informed that GOX@nGO-PEG-RhB and GOX@nGO-PEG-FITC could effectively respond to the fluctuation of glucose level as electrochemical biosensor.The present work presents special platforms for the immobilization of enzymes like GOX and provides new-type biosensors in the detection of glucose levels.

Coumarin-based two-photon AIE fluorophores: Photophysical properties and biological application

Based on the coumarin skeleton, we deliberately designed two groups of fluorophores, termed as CoumR and Naph-Coum-R, using the diphenylamino group as the electron donor, which displayed longwavelength emissions(red spectral region), large Stokes shift(up to 204 nm), superior AIE performance,and large two-photon absorbance cross-sections(as high as 365 GM). The electron-withdrawing substituents at the 3-position of these dyes could induce a significant red-shift in their emission spectra.Preliminary imaging experiments demonstrated the capability of these dyes as two-photon fluorophores for specifically staining lipid droplets in living cells.

Rationally designed meso-benzimidazole-pyronin with emission wavelength beyond 700 nm enabling in vivo visualization of acute-liver-injury-induced peroxynitrite

Fluorescent dyes with fluorescence emission above 700 nm are favorable for bio-imaging due to the higher tissue transparency and lower background fluorescence. In this study, we present a mesobenzimidazole-pyronin platform(Si BMs) with fluorescence emission maxima above 700 nm, which possess good cell permeability, photostability, and lysosomal localization. The great photophysical properties of the Si BMs encouraged us to further exploit their application toward bio-imaging. We synthesized the reduced ‘dihydro’ derivative HSi BM3 for sensing ONOO^(-), with high selectivity and sensitivity and a fast fluorescence “off-on” response(within 2 s). Then, we confirmed the potential of HSi BM3 for visualizing exogenous and endogenous ONOO-in cells and mice. More importantly, HSi BM3 was successfully employed for visualizing acute-liver-injury-induced peroxynitrite.

Apoptosis susceptibility of tumor cells to arsenic trioxide and the inherent cellular level of reactive oxygen species

OBJECTIVE: To explore the association of inherent cellular reactive oxygen species (ROS) levels with susceptibility of the tumor cells to apoptosis induction by arsenic trioxide (As(2)O(3)). METHODS: Low concentration (2 micromol/L) of As(2)O(3) was administered to two cultured leukemic cell lines, NB4 and U937, and two esophageal carcinoma cell lines, EC1.71 (also named EC/CUHK1) and EC1867, to confirm the difference in apoptosis susceptibility of NB4 versus U937 and of EC1.71 versus EC1867. Dihydrogenrhodamine 123 (DHR123), used as a ROS capture agent, was incubated with cells in the absence of As(2)O(3). Fluorescence intensity of rhodamine 123, the product of cellular oxidation of DHR123, was detected by flow cytometry and ROS was measured. RESULTS: Low concentration of As(2)O(3) induced apoptosis was more likely to occur in NB4 and EC1.71 cells than in U937 and EC1867 cells, or NB4 was more sensitive than U937, and EC1.71 more sensitive than EC1867 to As(2)O(3). The inherent cellular ROS level is higher in NB4 than in U937, and also higher in EC1.71 than in EC1867. CONCLUSIONS: The difference in cellular ROS level is positively associated with cellular susceptibility to apoptosis induction by As(2)O(3). The inherent ROS level might be important in defining apoptotic susceptibility to As(2)O(3).

Review on Recent Developments of Fluorescent Oxygen and Carbon Dioxide Optical Fiber Sensors

Oxygen and carbon dioxide sensors are involved in many chemical and biochemical reactions. Consequently, considerable efforts over years have been devoted to discover and improve suitable techniques for measuring gas concentrations by optical fiber sensors. Optical gas sensors consist of a gas-sensitive dye entrapped in a matrix with a high permeability to gas. With such sensors, gas concentration is evaluated based upon the reduction in luminescence intensity caused by gas quenching of the emitting state. However, the luminescence quenching effect of oxygen is highly sensitive to temperature. Thus, a simple, low-cost plastic optical fiber sensor for dual sensing of temperature and oxygen is presented. Also, a modified Stern-Volmer model is introduced to compensate for the temperature drift while the temperature is obtained by above dual sensor. Recently, we presented highly-sensitive oxygen and dissolved oxygen sensors comprising an optical fiber coated at one end with platinum （II） meso-tetrakis（pentafluorophenyl）porphyrin （PtTFPP） and PtTFPP entrapped core-shell silica nanoparticles embedded in an n-octyltriethoxysilane（Octyl-triEOS）/tetraethylorthosilane （TEOS） composite xerogel. Also, two-dimensional gas measurement for the distribution of chemical parameters in non-homogeneous samples is developed and is of interest in medical and biological researches.