Search

Multi‐level anticounterfeiting tags have been developed using a combination of different materials. Polyvinyl alcohol (PVA) mixed with titanium dioxide (TiO2) is used to produce flexible substrates. Fluorescent Opuntia Ficus‐indica (OFI) extract dissolved with polymethyl methacrylate (PMMA) is then sprayed over the substrate to create a random, yet unique deposition of droplets. Photographs of the tags are taken under UV illumination at different angles and analyzed through the scale‐invariant feature transform (SIFT) algorithm to extract their unique features. The SIFT analysis reveals hundreds to thousands of matched features when a given tag is compared with itself, whereas this number drops to tens for different tags. To enhance the security of the tags, ITO is sputtered onto one of them in the form of a pattern formed by a patch array exhibiting a specific fingerprint at terahertz (THz) frequencies. The evaluation of ITO reflectance shows that each patch array has a unique and unpredictable response stemming from its distinct electro‐optical characteristics. The non‐deterministic response of sprayed dye droplets and ITO patches enables the realization of two‐level authentication, which is difficult to replicate at a reasonable cost. The simple manufacturing process and inexpensive materials involved make the proposed tags easily integrable into packaging. [ABSTRACT FROM AUTHOR]

Comprehensive Summary A new fluorescent fingerprint powder (DFF‐MMT) was formulated by blending cyclic chalcone dye DFF with montmorillonite (MMT), which can develop latent fingerprints (LFPs) with exceptional resolution and contrast on various surfaces, including ordinary glass, tin foil, marble, LED screens, and materials with distinct colors and fluorescent backgrounds. The fluorescence of DFF‐MMT transforms from orange to bright yellow with LFPs, allowing for a flawless visualization of fingerprints on uneven surfaces or materials with static electricity. Impressively, fingerprints developed by DFF‐MMT can be stored for over 21 months and conveniently duplicated. The developed LFPs by DFF‐MMT still keep high quality under the influence of aquatic condition, illumination and thermal effects. DFF‐MMT also exhibits benefits, such as affordability, real‐time, high‐resolution, high‐contrast development and no damage to DNA, making it an ideal choice for sophisticated criminal investigations. [ABSTRACT FROM AUTHOR]

Near‐infrared (NIR) fluorescent probes with aggregation‐induced emission (AIE) properties are of great significance in cell imaging and cancer therapy. However, the complexity of its synthesis, poor photostabilities, and expensive raw materials still pose some obstacles to their practical application. This study reported an AIE luminescent material with red emission and its application in in vitro imaging and photodynamic therapy (PDT) study. This material has the characteristics of simple synthesis, large Stokes shift, good photostabilities, and excellent lipid droplets‐specific testing ability. Interestingly, this red‐emitting material can effectively produce reactive oxygen species (ROS) under white light irradiation, further achieving PDT‐mediated killing of cancer cells. In conclusion, this study demonstrates a simple approach to synthesize NIR AIE probes with both imaging and therapeutic effects, providing an ideal architecture for constructing long‐wavelength emission AIE materials. [ABSTRACT FROM AUTHOR]

A novel organic fluorescent material, namely 2,6-di([1,1'-biphenyl]-4-yl)-4-(perfluorophenyl)hepta-1,6-diene-1,1,7,7-tetracarbonitrile (DBPDT), has been synthesized and characterized in this study. Due to the special molecular packing mode in the solid state, J-aggregation, DBPDT displayed red-shifted emission compared with that in dilute solution. In this study, it was found that DBPDT showed aggregation-induced enhanced emission (AIEE) and solvatochromic properties. Assisted by quantum chemistry calculations, optical response properties to external electric field (EEF) were investigated, where it was found that external electric field (EEF) would affect the structures and optical properties of DBPDT distinctly. The optical response characteristics of DBPDT can provide an alternative structure for constructing advanced photoelectric functional materials. A novel organic fluorescent material, namely 2,6-di([1,1'-biphenyl]-4-yl)-4-(perfluorophenyl)hepta-1,6-diene-1,1,7,7-tetracarbonitrile (DBPDT), has been synthesized and characterized in this study. Assisted by quantum chemistry calculations, optical response properties to external electric field (EEF) were investigated, where it was found that external electric field (EEF) would affect the structures and optical properties of DBPDT distinctly. [ABSTRACT FROM AUTHOR]

Passive daytime radiative cooling has emerged as a promising green technology for the thermal management of buildings, vehicles, textiles, and electronics. Typically, both high solar reflectance and high thermal emissivity are prerequisites to achieve sufficient daytime cooling. However, colored radiative cooling materials are facing the dilemma of introducing visible light absorption, leading to challenges in balancing cooling and aesthetic demands. Here, three colored bilayer radiative cooling coatings, each comprised of a white base layer and a colored top layer with fluorescence enhancement are fabricated. Three phosphors (Sr2Si5N8:Eu2+, Y3Al5O12:Ce3+, and (Ba,Sr)SiO4:Eu2+) are employed with respective photoluminescence quantum yields (PLQYs) of 81%, 95.8%, and 91.0% as the colored pigment in the top layer. To mitigate the contradiction between coloration and solar reflectance, SiO2 microspheres are introduced into the top layer and utilize their Mie‐resonance‐based multiple scattering to increase the photoluminescent (PL) properties of the phosphors, which jointly boosts the effective solar reflectance (ESR) of the top layer. As a result, the three bilayer coatings exhibit soft colors while achieving subambient cooling with temperature drops of up to 1.5 °C. This fluorescence‐enhancement strategy may pave the way for preparing highly efficient radiative cooling coatings with tunable colors. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Molecular Science is the property of Journal of Molecular Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study presents the physical properties of fluorescent material-doped E7 nematic liquid crystals (NLC). Indium phosphide/zinc sulfide (InP/ZnS) quantum dots and rubrene dye were preferred as fluorescent materials. In order to examine the effect of different fluorescent materials on the physical properties of E7 NLC, the phase transition temperatures, wavelength-dependent absorbance values, and the electro-optical and dielectric parameters of composites were determined. The obtained results showed that both InP/ZnS quantum dots and rubrene dye change the electro-optical and dielectric properties of E7 NLC. According to this, it is thought that fluorescent material-doped NLC composites could become a focus of interest for future electro-optical device applications. [ABSTRACT FROM AUTHOR]

The structure used in this study is as follows: substrate/PMMA/ZnS/Ag/MoO3/NPB/Alq3/LiF/Al. Here, PMMA serves as the surface flattening layer, ZnS/Ag/MoO3 as the anode, NPB as the hole injection layer, Alq3 as the emitting layer, LiF as the electron injection layer, and aluminum as the cathode. The properties of the devices with different substrates were investigated using P4 and glass, developed in the laboratory, as well as commercially available PET. After film formation, P4 creates holes on the surface. The light field distribution of the device was calculated at wavelengths of 480 nm, 550 nm, and 620 nm using optical simulation. It was found that this microstructure contributes to light extraction. The maximum brightness, external quantum efficiency, and current efficiency of the device at a P4 thickness of 2.6 μm were 72,500 cd/m2, 1.69%, and 5.68 cd/A, respectively. However, the maximum brightness of the same structure with PET (130 μm) was 9500 cd/m2. The microstructure of the P4 substrate was found to contribute to the excellent device performance through analysis of the AFM surface morphology, film resistance, and optical simulation results. The holes formed by the P4 substrate were created solely by spin-coating the material and then placing it on a heating plate to dry, without any special processing. To confirm the reproducibility of the naturally formed holes, devices were fabricated again with three different emitting layer thicknesses. The maximum brightness, external quantum efficiency, and current efficiency of the device at an Alq3 thickness of 55 nm were 93,400 cd/m2, 1.7%, and 5.6 cd/A, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Molecular Science is the property of Journal of Molecular Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, polymer-dispersed liquid crystal (PDLC) films were prepared from a mixture of prepolymer, liquid crystal and phosphor-loaded reticular nanofibres films by a polymerisation-induced phase separation (PIPS) process. By comparing the microstructure and electro-optical curves of samples with different ratios of monomer types and liquid crystal contents, it was demonstrated that the cavity size of the polymer network had a significant effect on the electro-optical properties of the PDLC films. Reticular nanofibres films loaded with different phosphor contents were introduced into the liquid crystal mixture samples and the changes in the polymer network, electro-optical and fluorescence properties of these samples were analysed using SEM images, electro-optical curves and fluorescence curves. The electro-optical and fluorescence properties as well as the fluorescence properties of reticulated nanofibres films doped with PDLCs loaded with fluorescent materials were found to be improved and the anti-ageing properties are also greatly increased. Therefore, the development of meshed nanofiber membrane-doped PDLC films with faster response time, better optoelectronic properties, and better fluorescence properties will greatly improve the applications of PDLC-based devices in smart windows, sensors, energy efficiency and Potential technical applications in flexible devices. [ABSTRACT FROM AUTHOR]

ISO standards exist for evaluating sunscreens, such as those based on visual inspection. This assessment yields subjective results and is thus unreliable. Therefore, to verify the results of the visual assessment of sunscreens, quantitative evaluation methods are necessary. These methods require the measurement of the total radiation energy that is diffusely transmitted in all directions. For the measurements, although an integrating sphere is widely used to measure diffusely transmitted radiation, a simpler measurement would contribute to the easy usage of quantitative and objective evaluation. We propose the use of fluorescent materials as an alternative method to characterize sunscreens. In this method, a layer containing a fluorescent material is placed behind the sunscreen, and when the excitation radiation transmitted through the sunscreen reaches the fluorescent layer, it emits fluorescence. The feasibility of this measurement method was evaluated through numerical analysis and it demonstrated that hemispheric transmittance can be measured when the fluorescent layer is of high concentration or thick. Additionally, a prototype fluorescent layer was fabricated, and also the results were compared with the amount of diffusely transmitted UV from several commercial sunscreens. This pilot evaluation measurement method showed that the UV shielding index shown on the package does not necessarily truly reflect the amount of UV energy transmitted through the sunscreen, thus failing to provide the expected protection. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) fluorescent probes with aggregation-induced emission (AIE) properties are of great significance in cell imaging and cancer therapy. However, the complexity of its synthesis, poor photostabilities, and expensive raw materials still pose some obstacles to their practical application. This study reported an AIE luminescent material with red emission and its application in in vitro imaging and photodynamic therapy (PDT) study. This material has the characteristics of simple synthesis, large Stokes shift, good photostabilities, and excellent lipid droplets-specific testing ability. Interestingly, this red-emitting material can effectively produce reactive oxygen species (ROS) under white light irradiation, further achieving PDT-mediated killing of cancer cells. In conclusion, this study demonstrates a simple approach to synthesize NIR AIE probes with both imaging and therapeutic effects, providing an ideal architecture for constructing long-wavelength emission AIE materials., (© 2024 John Wiley & Sons, Ltd.)

A facile synthetic strategy has been established for the microwave‐assisted construction of two C−C bond via regioselective double arylation of imidazo[1,2‐a]pyridines with 1,2‐diiodobenzene by employing Pd(OAc)2 as a catalyst. The current protocol exhibited a simple, efficient and ligands free synthesis of 1‐phenylbenzo[a]imidazo[5,1,2‐cd]indolizine derivatives in good to excellent yields. This Pd‐catalyzed dual arylation provided a valuable tool for the discovery of fluorescent materials. [ABSTRACT FROM AUTHOR]

This is an overview of the state-of-the-art in the field of starch-based materials,incorporating recent research to provide a comprehensive look at developments involving novel materials. The properties of materials, and the fabrication techniques used, for starch- based bio nanocomposites are addressed here. Nanomaterials with high aspect ratio have significant potential for use as reinforcement in a starch matrix. Good adhesion between starch and fillers is essential to enhance properties. Fabrication methods, properties and applications of starch-based intelligent pH sensitive films and carbon dots are also discussed. Further, different drying methods, morphology, and thermal, mechanical and thermal conductivity properties of starch-based aerogels are highlighted. This polysaccharide is considered to be among the most prominent biocompatible and environmentally friendly precursors for the synthesis of advanced materials.

The structure used in this study is as follows: substrate/PMMA/ZnS/Ag/MoO3/NPB/Alq3/LiF/Al. Here, PMMA serves as the surface flattening layer, ZnS/Ag/MoO3 as the anode, NPB as the hole injection layer, Alq3 as the emitting layer, LiF as the electron injection layer, and aluminum as the cathode. The properties of the devices with different substrates were investigated using P4 and glass, developed in the laboratory, as well as commercially available PET. After film formation, P4 creates holes on the surface. The light field distribution of the device was calculated at wavelengths of 480 nm, 550 nm, and 620 nm using optical simulation. It was found that this microstructure contributes to light extraction. The maximum brightness, external quantum efficiency, and current efficiency of the device at a P4 thickness of 2.6 μm were 72,500 cd/m2, 1.69%, and 5.68 cd/A, respectively. However, the maximum brightness of the same structure with PET (130 μm) was 9500 cd/m2. The microstructure of the P4 substrate was found to contribute to the excellent device performance through analysis of the AFM surface morphology, film resistance, and optical simulation results. The holes formed by the P4 substrate were created solely by spin-coating the material and then placing it on a heating plate to dry, without any special processing. To confirm the reproducibility of the naturally formed holes, devices were fabricated again with three different emitting layer thicknesses. The maximum brightness, external quantum efficiency, and current efficiency of the device at an Alq3 thickness of 55 nm were 93,400 cd/m2, 1.7%, and 5.6 cd/A, respectively.

We investigated the effects of fluorescent material doping on the morphology, electro-optical, and fluorescence properties of PDLC films. The acrylate-based PDLC films prepared by polymerisation induced phase separation via UV curing method were doped with fluorescent material. The impact of fluorescent material on the microstructure was studied using scanning electron microscopy. The effect of fluorescent material on the electro-optical properties of PDLC films was studied by liquid crystal composite parameter tester. The electro-optical study revealed that the addition of fluorescent material results in the reduction of rise time, threshold voltage. The development of fluorescent material doped PDLC films with faster rise time, lower threshold voltage and lower saturation voltage will significantly enhance the potential technological applications of PDLC-based devices for smart windows, sensors and flexible devices. [ABSTRACT FROM AUTHOR]

A high-performance, multi-functional eugenol-based epoxy resin (EBER) was successfully prepared. The mechanical property, photochromism and fluorescence of EBER were investigated by tensile test, cyclic tensile test, ultraviolet–visible (UV–vis) spectrophotometer and fluorescence spectrometer. The results of tensile test and cyclic tensile test revealed that EBER has good mechanical property, even when it is compared with commercial epoxy resin. The UV − vis spectra displayed that EBER has photochromic functionality. After EBER was exposed to UV, the color of it will change from yellow to green, so the curing condition can be observed according to its color. The fluorescence spectrum exhibited that EBER has fluorescence. In the dark and under UV, EBER will display a jade-green fluorescence, which can help people observe the condition of the adhesive clearly. More importantly, this photochromic fluorescent EBER was prepared from raw materials without dye and fluorescent agent, thereby can solve a lot of problems. This work provides a new idea and method for preparing high-performance, multi-functional bio-based epoxy resin, and has a potential application in bronze ware repairment. [ABSTRACT FROM AUTHOR]

A series of cellulose-based fluorescent materials are prepared under relative mild conditions by use of the DMSO/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/CO2 system to utilize as coating pigments. Through the observation under 365 nm UV light, the cellulose-based fluorescent materials exhibit good fluorescence response and bright color. Furthermore, due to the limitation of the molecular skeleton of cellulose, the intrinsic aggregation caused quenching phenomenon commonly existed in conventional organic fluorescent pigments can be effectively inhibited, which is very helpful to retain good fluorescence response in epoxy-based coating material and its coating films. Moreover, the addition of cellulose-based fluorescent materials also increases the mechanical properties of the coating film. The increase of tensile strength and tensile modulus respectively reaches ~39% and ~66%. Solvent resistance and thermal property of the coating films generally remain unchanged. The fabrication of cellulose-based fluorescent materials in DMSO/DBU/CO2 system provides a feasible way to develop the functional application of cellulose. [ABSTRACT FROM AUTHOR]

Fluorescent imaging in living animals gives an intuitive picture of the dynamic processes in the complex environment within a living being. However, animal tissues present a substantial barrier and are opaque to most wavelengths of visible light. Fluorescent nanoparticles (NPs) with new photophysical characteristics have shown excellent performance for in vivo imaging. Hence, fluorescent NPs have been widely studied and applied for the detection of molecular and biological processes in living animals. In addition, developments in the area of nanotechnology have allowed materials to be used in intact animals for disease detection, diagnosis, drug delivery, and treatment. This review provides information on the different types of fluorescent particles based on nanotechnology, describing their unique individual properties and applications for detecting vital processes in vivo. The development and application of new fluorescent NPs will provide opportunities for in vivo imaging with better penetration, sensitivity, and resolution. This article is categorized under:Diagnostic Tools > in vivo Nanodiagnostics and Imaging [ABSTRACT FROM AUTHOR]

In this study, we fabricated non-toxic, highly stable, eco-friendly carbon nanodots (CD) from laboratory paper waste through a facile synthetic approach. The paper waste was converted to carbon by thermal decomposition. The carbon powder obtained was dispersed in acid using a sonication process. Subsequently, the CD was separated by centrifugation and filtration. The morphological properties of the prepared CD were analyzed using atomic force microscopy (AFM). The optical behavior of the CD was assessed using a UV–vis and fluorescence spectrophotometer. The AFM results clearly indicated that the CD had a spherical shape and sizes of ∼3–10 nm. The CD exhibited excitation-dependent photoluminescence. Finally, we assessed the metal ion selectivity of the paper waste derived CD, and utilized it as a fluorescent probe to detect Fe3+ ions. This CD fabrication approach is sustainable, cheap, and uses a renewable precursor. It also may enable the valorization of laboratory paper waste to high-value products.

ISO standards exist for evaluating sunscreens, such as those based on visual inspection. This assessment yields subjective results and is thus unreliable. Therefore, to verify the results of the visual assessment of sunscreens, quantitative evaluation methods are necessary. These methods require the measurement of the total radiation energy that is diffusely transmitted in all directions. For the measurements, although an integrating sphere is widely used to measure diffusely transmitted radiation, a simpler measurement would contribute to the easy usage of quantitative and objective evaluation. We propose the use of fluorescent materials as an alternative method to characterize sunscreens. In this method, a layer containing a fluorescent material is placed behind the sunscreen, and when the excitation radiation transmitted through the sunscreen reaches the fluorescent layer, it emits fluorescence. The feasibility of this measurement method was evaluated through numerical analysis and it demonstrated that hemispheric transmittance can be measured when the fluorescent layer is of high concentration or thick. Additionally, a prototype fluorescent layer was fabricated, and also the results were compared with the amount of diffusely transmitted UV from several commercial sunscreens. This pilot evaluation measurement method showed that the UV shielding index shown on the package does not necessarily truly reflect the amount of UV energy transmitted through the sunscreen, thus failing to provide the expected protection.

A polyazomethine poly-2,2’-hexamethylenebis(oxybenzaldehyde)-1,5-naphthalenediimine (PoHOBND) was prepared by polycondensation reaction of dialdehyde and 1,5-naphthlenediamine. The polymer was characterized through elemental microanalysis, FT-IR, 1HNMR, SEM, UV–Visible spectroscopy, fluorescence and thermal analysis. The polyazomethine (PoHOBND) showed violet colored fluorescence emissions and its thermal stability was up to 630˚C. The antimicrobial activities of the polyazomethine (PoHOBND) were also studied. An effective method was produced and employed at optimum conditions in remediation of Ni (II), Cu (II) and Co (II) from sewage wastewater samples and polyazomethine (PoHOBND) was used as sorbent. The sorption factors (adsorbate concentration, sorbent amount, shaking duration and pH) were optimized through multi-variant technique by using factorial design based on eighteen batch experiments. The metal ions present in wastewater were determined through AAS. The polyazomethine (PoHOBND) removed up to 77% Ni (II), 98% Cu (II) and 72% Co (II) from wastewater with RSD within 0.26–3.62%. The adsorption of Ni (II), Cu (II), and Co (II) on polyazomethine surface was confirmed through SEM images and EDX analysis. Kinetics and equilibrium of the adsorption were also examined. The sorption process of Ni (II), Cu (II), and Co (II) obeyed Langmuir isotherm with adsorption capacities of 25.64, 15.38 and 31.25 mg g−1 respectively and their kinetic results best suited to pseudo-second-order. [ABSTRACT FROM AUTHOR]

A novel two-dimensional Zn(II) coordination polymer [Zn(II) CP], [{Zn(L)Zn(OAc–)(µ-OAc–)}4]n· 2nCH3CH2OH has been self-assembled from Zn(OAc)2·2H2O. It contains pyridine-terminal salamo-type ligand H2L. Structure of the product has been determined. The Zn(II)CP contains two kinds of Zn(II) ions of different coordination modes. The Zn1 center is characterized by five-coordinated triangular biconical geometry. The Zn2 center is a six-coordinated octahedral center. Using these as junction points and the fully deprotonated ligand (L)2– moieties containing pyridine-terminal as a linker, the 2-D coordination polymer with two kinds of different pores [27.47 × 11.77(23) Å2; 11.97 × 4.51(17) Å2] has been obtained. The Zn(II) CP can fluoresce green and be used in fluorescent materials. Short-range interactions on Zn(II) CP surface have been studied by Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

Four types of unprecedented and chemodivergent reactions between α-diketones and alkynyl α-diketones have been achieved under the catalysis of phosphine and Brønsted base, respectively, leading to the rapid construction of four different classes of biologically important but synthetically challenging molecular scaffolds including 2-hydroxyfuran-3(2H)-ones, 4-hydroxy-2-oxabicyclo[2.2.1]heptan-3-ones, 1,3-diaryl cyclobutanes, and 4-(furan-2(3H)-ylidene)cyclopent-2-enones. The formation of the products includes two novel rearrangement processes, and further transformations on the products can be easily achieved to deliver value-added substances such as highly functionalized cyclopentanes. Moreover, the 2-hydroxyfuran-3(2H)-one products display promising photophysical properties such as green luminescence under UV light and aggregation-induced emission effect, showing the practical application value of this work. The great potential of α-diketones in both synthetic chemistry and material science has been unambiguously demonstrated. [ABSTRACT FROM AUTHOR]

The 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt (PTSA) is a pyrene derivative with high fluorescence characteristics and is widely used in fluorescence tracer. This study aims at investigating a simple and fast fluorescence detection method for determining the concentration of ferric ion by using PTSA, which the principle is that the fluorescence quenching of PTSA by ferric ions. Theoretical and experimental methods were adopted to deeply analyze its detection performance and characteristics. The fluorescence quenching phenomena under different pH conditions and the effect of the different interfering metal ions on PTSA/Fe3+ system was studied. The results showed that the PTSA was quite promising for the fluorescence detection of trace ferric ions, and the limit of detection is 9 μg/L. This study is envisioned to provide inspirational insights on trace detection of iron ions, opening new routes for water monitoring use fluorescence properties. [ABSTRACT FROM AUTHOR]

Fluorescence imaging has been widely used as a powerful tool for in situ and real-time visualization of important analytes and biological events in live samples with remarkably high selectivity, sensitivity, and spatial resolution. Compared with one-photon fluorescence imaging, two-photon fluorescence imaging exhibits predominant advantages of minimal photodamage to samples, deep tissue penetration, and outstanding resolution. Recently, the aggregation-induced emission (AIE) materials have become a preferred choice in two-photon fluorescence biological imaging because of its unique bright fluorescence in solid and aggregate states and strong resistance to photobleaching. In this review, we will exclusively summarize the applications of AIE-active materials in two-photon fluorescence imaging with some representative examples from four aspects: fluorescence detection, in vitro cell imaging, ex vivo tissue imaging, and in vivo vascular imaging. In addition, the current challenges and future development directions of AIE-active materials for two-photon bioimaging are briefly discussed.

Metal‐organic frameworks (MOFs) as a class of porous functional materials have attracted more and more attention for biomedical applications. To date, MOFs have been developed for bioimaging based on a series of advantages such as the large surface areas, high porosity, fluorescence functionalities and good biocompatibility. It is worth noting that organic or inorganic fluorescent materials such as fluorescent dyes, quantum dots, metal nanoclusters and nanosheets can combine MOFs or be encapsulated in MOFs to form fluorescent nanocomposites for excellent imaging function. Importantly, excellent imaging capabilities are of great significance in living cells and in vivo for detection, diagnosis and cancer therapy. In this review, we focus on the recent research of the bioimaging in living cells and in vivo based on various MOF‐based nanocomposites and their potential biological clinical applications. [ABSTRACT FROM AUTHOR]

Metal‐organic frameworks (MOFs) as a class of porous functional materials have attracted more and more attention for biomedical applications. To date, MOFs have been developed for bioimaging based on a series of advantages such as the large surface areas, high porosity, fluorescence functionalities and good biocompatibility. It is worth noting that organic or inorganic fluorescent materials such as fluorescent dyes, quantum dots, metal nanoclusters and nanosheets can combine MOFs or be encapsulated in MOFs to form fluorescent nanocomposites for excellent imaging function. Importantly, excellent imaging capabilities are of great significance in living cells and in vivo for detection, diagnosis and cancer therapy. In this review, we focus on the recent research of the bioimaging in living cells and in vivo based on various MOF‐based nanocomposites and their potential biological clinical applications. [ABSTRACT FROM AUTHOR]

Forensic chemistry deals with the analysis of various types of physical evidences related to crime, corresponding to the detection of target substances or elements in complex matrices. There is a vital need for highly selective, rapid, and sensitive biosensing technologies in heavy metal ions analysis especially those from living persons, autopsy, food, water, soil, and other identified substances at very preliminary stages. Fluorescent materials-based method for heavy metal ions detection is one of the most important analytical methods, resulting in the ability to measure analytes in complex matrices with unsurpassed selectivity and sensitivity. In this mini review, different fluorescent materials-based analytical methods aiming at several heavy metal ions detection are exclusively reviewed through a comprehensive literature survey. In addition, current challenges to achieve integrated evidence analysis process are briefly discussed to provide an outlook for heavy metal ions detection based on fluorescent analytical methods in the forensic chemistry field.

A highly fluorescent composite powder based on graphitic carbon nitride (g-C3N4) is synthesized by thermal decomposition of melamine in the presence of nanoparticles of aluminum, titanium, and silicon oxides. The fluorescent properties of the composite nanoparticles excited at a wavelength of 532 nm are studied. The relative fluorescence quantum yield of the obtained material is 62%. [ABSTRACT FROM AUTHOR]

Chalcone is an aromatic ketone that forms the central core of many important biological compounds, which are known as chalcones. Chalcones are the biogenetic precursors of flavonoids and isoflavonoids, which are abundant in plants. Chalcones are active lead molecules in medicinal chemistry for the discovery of new drugs. Here, we review properties, biosynthesis and structural diversity of natural chalcones. Then, we present the synthesis of chalcones and their biological activities with focus on structure–activity relationships. Pharmaceutically important and patented chalcones are also discussed. [ABSTRACT FROM AUTHOR]

Eu3+ doped Y2P4O13 phosphors were prepared by hydrometallurgical method. The crystal structure and fluorescence properties of the as-synthesized products were investigated by powder X-ray dillraction(XRD), Fourier Transferred Infrared Spectroscopy (FT-IR) and Fluorescence Spectroscopy (FL), The influences of the n(Y + Eu)/n(P) ratio of the starting materials, the kind of the pH regulators on the phase structures and fluorescence properties of the asprepared samples were analyzed. The results showed that the n(Y+Eu)/n(P) ratio of the starting materials and the kind of the pH regulators have direct influence on the phase structures and fluorescence properties of the obtained samples. The Eu3+ doped Y2P4O13 crystals with orthorhombic structure were successfully synthesized when the n(Y+Eu)/n(P) ratio of the starting materials is 1 : 2.1, and the NH3HCO3 was used as pH regulators with 6. The Eu3+ doped Y2P4O13 samples can be effectively excited by 395 nm lightï?Œand emit intensive orange-red light with color. [ABSTRACT FROM AUTHOR]

Fluorescent nanoprobes are highly desirable toolkit for bioimaging applications. This study reports the first example for the synthesis of a nontoxic prototypical fluorescent organic compound 2‐benzo[d]thiazol‐2‐yl)‐3‐(2‐chloro‐4‐(dimethylamino)phenyl)acrylonitrile (BCA) and its entrapment into the poly[cyclotriphosphazene‐co‐polyethyleneimine] cross‐linked (PCPEI) nanospheres named as BCA@PCPEI for targeted cell imaging application. The as‐prepared BCA@PCPEI nanospheres were thoroughly characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and phosphorus‐31 nuclear magnetic resonance (31P‐NMR) analyses. The surface functional analysis of the nanospheres was performed by X‐ray photoelectron spectroscopy (XPS), which proves that the content ratios of elements belong to the precursors concentrations. The as‐prepared nanospheres displayed emission at 606 nm with bright orange fluorescence at any concentration. Moreover, the nanospheres were also less cytotoxic and maintained remarkable cell viability up to 100 μg/mL. Owing to the fluorescence with higher emission, this material has shown excellent cell imaging performance with better targeting ability to HeLa cells. [ABSTRACT FROM AUTHOR]

Abstract It is still a matter of worldwide continuous concern about how to obtain efficient, stable, pure blue light emitting materials and apply them in industrialized OLED devices. Here, a novel deep blue fluorescent material 2-(4'-(9 H -carbazol-9-yl)-[1,1′-biphenyl]-4-yl)-1-(4-methoxyphenyl)-1 H -phenanthro [9,10-d]imidazole(CzB-MOPPI) was firstly designed, synthesized and employed as emitters for deep-blue OLEDs. CzB-MOPPI, with carbazole as donor, twisted biphenyl bonded phenanthroimidazole which contains rigid plane structure as acceptor, exhibits high thermal stability with decomposition temperature (T d) of 480 °C. Weak donor carbazole unit and twist biphenyl both make the compound emit less red shift meanwhile maintain in deep blue region. The non-doped OLEDs based on the CzB-MOPPI as emitter show maximum emission at 435 nm, maximum luminance of 6450 cd/m2, maximum current efficiency (CE) of 3.34 cd/A. The chromaticity coordinate is (0.16, 0.08) which is extremely close to the NTSC standard blue. In Particular, the devices show an impressive external quantum efficiency (EQE) as high as 5.97%. Graphical abstract Image 1 Highlights • A donor-acceptor type deep blue fluorescent material was firstly designed and synthesized. • Compound exhibits high thermal stability and bipolar properties. • OLED devices were fabricated, showing deep blue emission and impressive high EQE of 5.97%. [ABSTRACT FROM AUTHOR]

Copyright of China Textile Leader is the property of China Textile Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We have developed a self-assembled fluorescent cluster comprising a seminaphthorhodafluor (SNARF) derivative protected by a photoremovable o-nitrobenzyl group. Prior to UV irradiation, a colorless and nonfluorescent cluster was spontaneously assembled in aqueous solution. After UV irradiation, the self-assembled cluster remained intact and showed a large enhancement in pH-responsive fluorescence. The unique pH responsive fluorescent cluster could be used as a dual-emissive ratiometric fluorescent pH probe not only in the test tube but also in HeLa cell cultures.

Lanthanide organometallic complexes exhibit strong luminescence characteristics, owing to their antenna effects. The f-d energy level transition causes this phenomenon, which occurs when ligands and the external electrons of lanthanide metals coordinate. Based on this phenomenon, we used two lanthanide metals, europium (Eu) and terbium (Tb), in the present study as the metal center for iminodiacetic acid ligands. Further, we developed the resulting fluorescent organometallic complex as a smart material. The ligand-metal bond in the material functioned as a metal chelating agent and a cross-linking agent in a dynamically coordinated form, thereby prompting the material to self-heal. Temperature-sensitive poly- N -isopropylacrylamide was incorporated into the material as the polymer backbone. Afterward, we combined it with water-soluble poly(vinyl alcohol) and an additional ligand from poly(acrylic acid) to fabricate a high-performance hydrogel composite material. The shrinkage and expansion of the polymer form a grid between the materials. Because of the different coordination stabilities of Eu 3+ and Tb 3+ , the corresponding material exhibits environmental responses toward excitation wavelength, temperature, and pH, thus generating different colors. When used in fabrics, the cross-linking mechanism of the material effectively looped the material between fabric fibers; furthermore, the temperature sensitivity of the polymer adjusted the size of pores between fabric fibers. At relatively higher temperatures (>32 °C), the polymer structure shrank, fiber pores expanded, and air permeability improved. Thus, this material appears to be promising for use in smart textiles.

Yellow–green fluorescent crystals of the title compound, C19H18O3, were obtained by the reaction of hydroxyacetophenone and 4-tert-butylbenzaldehyde with hydrogen peroxide as oxidant. The plane of the benzene ring is slightly twisted to the mean plane of the 4H-chromene-4-one moiety (r.m.s. deviation = 0.0191 Å) by 10.53 (8)°. In the crystal, molecules are linked by pairs of O—H...O hydrogen bonds, forming inversion dimers with an R22(10) ring motif. The dimers are linked via C—H...π interactions, forming sheets parallel to (10-1).

As a typical water-soluble synthetic azo pigment, tartrazine is widely used in food products, and its abuse was harmful to our health. Hence, it is very important to establish a facile and economical method to detect the tartrazine content in food. In the current study, the crayfish shell carbon quantum dots (CS-CQDs) were prepared through a facile hydrothermal approach from crayfish shells. The CS-CQDs exhibited strong fluorescent emissions at 462 nm under the excitation wavelength of 380 nm. The CS-CQDs were demonstrated to react with the synthetic pigments tartrazine selectively and effectively with a limit of detection (LOD) of 0.48 μM in the linear range of 0–70 μM. The Stern-Volmer equation and thermodynamic analysis revealed that the fluorescence quenching was a spontaneous static quenching and mainly driven by van der Waals interactions and hydrogen bonds. Furthermore, the CS-CQDs sensor was applied in energy beverage and durian candy samples with acceptable recovery of 92.7–104.5% and low RSD. Finally, we successfully designed a fluorescent test strip using CS-CQDs and filter paper. The current CS-CQDs had the potential ability to construct a simple paper strip for the detection of tartrazine in the future, which was useful for the food industry. [Display omitted] • Carbon quantum dots (CS-CQDs) were prepared from crayfish shells. • CS-CQDs can be used for the trace detection of tartrazine in food samples. • The interaction between CS-CQDs and tartrazine was major a static quenching. • The general visual detection of tartrazine was realized by the test strips. [ABSTRACT FROM AUTHOR]

We have developed a self-assembled fluorescent cluster comprising a seminaphthorhodafluor (SNARF) derivative protected by a photoremovableo-nitrobenzyl group. Prior to UV irradiation, a colorless and nonfluorescent cluster was spontaneously assembled in aqueous solution. After UV irradiation, the self-assembled cluster remained intact and showed a large enhancement in pH-responsive fluorescence. The unique pH responsive fluorescent cluster could be used as a dual-emissive ratiometric fluorescent pH probe not only in the test tube but also in HeLa cell cultures. [ABSTRACT FROM AUTHOR]

Abstract Carbon nanotubes (CNTs) were covalently modified by fluorescence ligand (glycine-N-8-quinolylamide) and formed a hybrid material which could be used as a selective probe for metal ions detection. The anchoring to the surface of the CNTs was carried out by the reaction between the precursor and the carboxyl groups available on the surface of the support. Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA) unambiguously proved the existence of covalent bonds between CNTs and functional ligands. Fluorescence characterization shows that the obtained organic–inorganic hybrid composite is highly selective and sensitive (0.2 μM) to Zn(II) detection.

Ticks transmit more pathogen species than any other group of blood-feeding arthropods worldwide, affecting humans, livestock, and companion animals. Hyalomma dromedarii is the predominant tick species infesting camels, and its effective control is of pivotal importance. In this research, we compared the phytoefficacy of safranin (SF), a fluorescent dye applied as an acaricide for the first time, to that of tetramethrin (TM) against engorged females of H. dromedarii through in vitro immersion bioassays. Furthermore, the effect of SF exposure was evaluated on the reproductive potential of surviving tick females. Different concentrations of SF (0.03, 0.06, 0.3, 1, and 4 % w: v) and TM (0.03, 0.13, 0.5, 2, and 4 %) were prepared in distilled water and administered to engorged females of H. dromedarii. SF-treated ticks were illuminated with a light source for 30 min post-treatment (PT). Photophysical properties of SF were studied, and the relative efficacy of the used light source and sunlight was calculated. Results showed that the minimum least concentration that causes 100 % acaricidal effect was 4 % PT with SF and TM, for 8 and 48 h, respectively. LC values 8 and 24 h PT were 0.08, 0.03 and 0.78, 0.20 %, respectively. Comparing LC and LC 2 h PT, SF was 33 and 22 times more potent than TM. LT of 4 % SF and TM were 0.80 and 2.17 h, respectively. Treatment with the lowest concentrations of SF and TM induced reduction of the number of ovipositing females, eggs per female, ticks laying viable eggs, and hatched eggs. Overall, our results highlighted that SF is highly effective if compared to TM, allowing use to candidate it for the development of novel and safer acaricides. [ABSTRACT FROM AUTHOR]

Lanthanide ions have attracted intense research interest for their luminescence properties, which make them interesting for applications such as bioactive probes for magnetic resonance and luminescence. We present here our study related to the interaction between DNA–CTMA (hexadecyltrimethylammonium chloride) and praseodymium. The new materials synthesized were investigated from photophysical properties and morphological point of view. [ABSTRACT FROM AUTHOR]

A mechanochromic composite comprises an excimer-forming fluorescent dye dispersed in a compatible polymeric host. Upon large deformation of the polymeric structure, a shift of the fluorescence emission from the excimer band to the monomer band is observed, due to reorganization of dye aggregates. Mechanochromic elastomers can be tailored to produce a reversible optical response during cyclic deformation. Here, we study the optomechanical properties of mechanochromic elastomers undergoing large uniaxial and biaxial deformations. Through detailed experiments and constitutive modeling, we relate the optical response of the mechanochromic elastomer to the deformation of the polymer network. We confirm that optical response is largely reversible and is modulated by the initial dye concentration in the polymer. We adapt the classical Arruda–Boyce model to elucidate microstructural modifications of the polymer–dye blend. We propose a constitutive hypothesis for the optical behavior of the material, which relates variations of the emission spectrum to surface stretching. This knowledge can aid in the design of strain and stress sensors for applications in mechanics, biomechanics, and life sciences. [ABSTRACT FROM AUTHOR]

A new organic imide dye based on tetrahydro[5]helicene skeleton was synthesized, and its helical structural feature was confirmed by the crystal structure. It was found that the dye exhibited remarkable and reversible acid/base stimulated fluorescence switching properties in both solution and solid state, in which the dye was changed from “D–A type” to “A–A type” in the presence of TFA, and returned to its original form upon the addition of TEA. This switchable behavior was also evidenced by the 1 H NMR experiments and theoretical calculations. [ABSTRACT FROM AUTHOR]