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

Double-layer orgainc 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/m2 at 17V.

Synthesis, properties and application of novel 5,6,5,6-tetracyclic pyrazine/pyrrole-fused unsymmetric bis（BF2） fluorescent dyes:BOPYPYs

Novel 5,6,5,6-tetracyclic pyrazine/pyrrole-fused unsymmetric bis(BF2) fluorescent dyes(BOPYPYs) were obtained by reaction of pyrrole-2-carboxaldehyde with 1-(pyrazin-2-yl)hydrazine in the presence of Et3 N-BF3·Et2 O for the first time.The absorption maxima of pyrazine-fused BOPYPY are obviously bathochromic shifts,in contrast to those of the reported BOPPY,indicating that the discrepant substitute groups between pyridine and pyrazine result in the remarkable wavelength difference.The new series of BO PYPYs possess high molar extinction coefficients,high fluorescence quantum yields,and larger Stokes shifts.A Knoevenagel reaction of BOPYPY with 4-dimethylaminobenzaldehyde smoothly produced the dye with the extension of π-conjugation.Dimethylamino-containing BOPYPY as a pH-responsive fluorescent sensor could detect pH value.

Aggregation Control of Hemicyanine Fluorescent Dye by Using of Cucurbit[7]uril and Pillar[6]arene

The aggregation of cyanine-based fluorescent dyes easily results in the fluorescence quenching,which limits the applications in biological science and materials science.So developing an efficient method to adjust the aggregation of cyanine dyes is very significant.In this work,we employ two different macrocyclic hosts pillar[6]arene(DEP[6])and cucurbit[7]uril(CB[7])to investigate their effects towards fluorescence spectra of dye 1.The result indicates that both of them can disrupt the aggregation of dye 1,resulting in the enhancement of its fluorescence intensity.Interestingly,investigation on the corresponding titration experiments of 1H NMR and density functional theory cal-culations shows that CB[7]and DEP[6]play different roles in the process of disaggregation.

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.

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.

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.

Development of aryl-containing dipyrrolyldiketone difluoroboron complexes(BONEPYs):Tune the hydrogen bond o-C—H…F for fluoride recognition

Dipyrrolyldiketone difluoroboron complexes(BONEPYs)were synthesized by condensation of the corresponding pyrroles and malonyl chloride followed by treatment with BF3·OEt2.The aryl-substituted pyrrole is introduced to form a cyclic system in order to investigate anion binding studies.In BONEPYs 1-3 the o-H of the aryl group forms hydrogen bonding with F to give a more table complex.In contrast,the intramolecular hydrogen-bonded BONEPY endo-4 is more stable than its exo isomer.While adding F,the hydrogen bonds must be broken first to give 4·(3)F.Owing to the electron-rich group(-OMe),the o-H of the phenyl group can hardly interact with F via hydrogen bonding to give the less stable complex4-(5)F.The energy diffe rences between the different conformations were calculated using DFT methods,which is consistent to the experimental observations.

Rational design of far red to near-infrared rhodamine analogues with huge Stokes shifts for single-laser excitation multicolor imaging

Rhodamine dyes have been widely employed in biological imaging and sensing. However, it is always a challenge to design rhodamine derivatives with huge Stokes shift to address the draconian requirements of single-excitation multicolor imaging. In this work, we described a generally strategy to enhance the Stokes shift of rhodamine dyes by completely breaking their electronic symmetry. As a result, the Stokes shift of novel rhodamine dye DQF-RB-Cl is up to 205 nm in PBS, which is the largest in all the reported rhodamine derivatives. In addition, we successfully realized the single excitation trichromatic imaging of mitochondria, lysosomes and cell membranes by combining DQF-RB-Cl with commercial lysosomal targeting probe Lyso-Tracker Green and membrane targeting dye Dil. This is the organic synthetic dyes for SLE-trichromatic imaging in cells for the first time. These results demonstrate the potential of our design as a useful strategy to develop huge Stokes shift fluorophore for bioimaging.

Development of environment-insensitive and highly emissive BODIPYs via installation of N,N'-dialkylsubstituted amide at meso position

Fluorescent dyes play a crucial role in fluorescence imaging and sensing technology.However,there is a dilemma that they are usually intrinsically hydrophobic which lacks of emission in water and modification with ionic groups to access water solubility may result in poor membrane permeability.Fluorescent dyes with strong fluorescence emission in both nonpolar and polar solvents are highly desirable.In this manuscript,we reported a strategy to develop fluorescent BODIPY dyes via installation of amide moiety at meso position of 1,3,5,7-tetramethyl-BODIPY and discovered that N,N'-dialkylsubstituted BODIPY amides possessed highly fluorescent emission with favorable environment-insensitive properties.

Lip print enhancement: review

Lip print(LP)evidence can be an essential tool for human forensics.LPs have conventionally been developed using substances such as lysochrome dyes,fluorescent dyes,indigo dye,aluminium powder,and silver metallic powder.However,techniques for LP enhancement from various substrates are currently inconsistent and lack standardisation in practice.This review summarises current knowledge on the physical and chemical techniques of LP enhancement,identifies limitations,and provides suggestions for future research on practical applications of cheiloscopy as a forensic tool in criminal justice.

Progress of Optically Encoded Microspheres for Multiplexed Assays

New initiatives put forward by clinical diagnosis require the development of technologies for high throughput screening(HTS) of multiple analytes. Suspension arrays have great advantages over the planar arraybased multiplexing assays, and the encoded bead is the key for providing multiplexing capability. Among various encoding strategies, optically encoded microspheres have been widely used while the number of codes is still limited. This review discusses the progress of optical encoding strategy from mainly three aspects, namely organic dyes, quantum dots(QDs) and surface-enhanced Raman scattering(SERS) active substrates. Emphases are put up on describing how these optical encoded microbeads are manufactured and the merits and demerits of different encoding materials are compared.

Split-HaloTag imaging assay for sophisticated microscopy of protein–protein interactions in planta

An ever-increasing number of intracellular multi-protein networks have been identified in plant cells.Split-GFP-based protein–protein interaction assays combine the advantages of in vivo interaction studies in a native environment with additional visualization of protein complex localization.Because of their simple protocols,they have become some of the most frequently used methods.However,standard fluorescent proteins present several drawbacks for sophisticated microscopy.With the HaloTag system,these drawbacks can be overcome,as this reporter forms covalent irreversible bonds with synthetic photostable fluorescent ligands.Dyes can be used in adjustable concentrations and are suitable for advanced microscopy methods.Therefore,we have established the Split-HaloTag imaging assay in plants,which is based on the reconstitution of a functional HaloTag protein upon protein–protein interaction and the subsequent covalent binding of an added fluorescent ligand.Its suitability and robustness were demonstrated using a well-characterized interaction as an example of protein–protein interaction at cellular structures:the anchoring of the molybdenumcofactor biosynthesis complex to filamentous actin.In addition,a specific interactionwas visualized in a more distinctivemannerwith subdiffractional polarizationmicroscopy,Airyscan,and structured illumination microscopy to provide examples of sophisticated imaging.Split-GFPand Split-HaloTag can complement one another,as Split-HaloTag represents an alternative option and an addition to the large toolbox of in vivo methods.Therefore,this promising new Split-HaloTag imaging assay provides a unique and sensitive approach formore detailed characterization of protein–protein interactions using specific microscopy techniques,such as 3D imaging,single-molecule tracking,and super-resolution microscopy.

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.

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.