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Structural adhesives that do not require heating are in high demand in the automotive and electronics industries. However, it remains a challenge to develop robust adhesives that rapidly achieve super adhesion near ambient temperature. Herein, a room-temperature curable, fast-bonding, and super strong epoxy-based structural adhesive was designed from the perspective of cross-scale structure, which lies in threefold pivotal aspects: (i) high branching topology of glycerol carbonate-capped polyurethane (PUGC) increases the kinetics of the ring-opening reaction, contributing to fast crosslinking and the formation of abundant urethane and hydroxyl moieties; (ii) asynchronous crosslinking of epoxy and PUGC synergistically induces phase separation of PUGC within the epoxy resin and the resulting PUGC domains surrounded by interpenetrated shell serves to efficiently toughen the matrix; (iii) abundant dynamic hydrogen bonds including urethane and hydroxyl moieties, along with the elastomeric PUGC domains, dissipate energy of shearing force. As a result, the adhesive strength rapidly grows to 16â MPa within 4â hours, leveling off to 21â MPa after 7â hours, substantially outperforming commercial room-temperature curable epoxy adhesives. The results of this study could advance the field of high-performance adhesives and provide valuable insights into designing materials for efficient curing at room temperature.
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Hypochlorous acid (HClO) is a reactive oxygen species and a relatively strong antibacterial substance in the immune defense system. The normal concentration of HClO in the human body is approximately 200 µM, and its high concentration can cause tissue damage and some diseases. Herein, a chromenoquinoline-based ratiometric fluorescent probe was developed to detect and quantify HClO. The developed Probe 1 exhibited the advantages of large Stokes shift (137 nm), high synthetic yield (84.7 %), simple synthesis method, short response time (<4 min), low detection limit (5.1 nM), and low toxicity. The probe was successfully validated in live cells and zebrafish.
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Colorantes Fluorescentes , Pez Cebra , Animales , Humanos , Ácido HipoclorosoRESUMEN
Strong and ductile adhesives often undergo both interfacial and cohesive failure during the debonding process. Herein, we report a rare self-reinforcing polyurethane adhesive that shows the different phenomenon of only interfacial failure yet still exhibiting superior adhesive strength and toughness. It is synthesized by designing a hanging adhesive moiety, hierarchical H-bond moieties, and a crystallizable soft segment into one macromolecular polyurethane. The former hanging adhesive moiety allows the hot-melt adhesive to effectively associate with the target substrate, providing sufficient adhesion energy; the latter hierarchical H-bond moieties and a crystallizable soft segment cooperate to enable the adhesive to undergo large lap-shear deformations through sacrificing weak bonds and mechano-responsive strength through the fundamental mechanism of strain-induced crystallization. As a result, this polyurethane adhesive can keep itself intact during the debonding process while still withstanding a high lap-shear strength and dissipating tremendous stress energy. Its adhesive strength and work of debonding are as high as 11.37 MPa and 10.32 kN m-1, respectively, outperforming most reported tough adhesives. This self-reinforcing adhesive is regarded as a new member of the family of strong and ductile adhesives, which will provide innovative chemical and structural inspirations for future conveniently detachable yet high-performance adhesives.
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Reactive oxygen species (ROS) play an important role in living activities as signaling molecules that regulate the living activities of organisms. There are many types of ROS, mainly including hydrogen peroxide (H2O2), hypochlorous acid (HOCl), hydroxyl radical (â¢OH), peroxyl radical (ROOâ¢), singlet oxygen (1O2), peroxynitrite (ONOO-) and superoxide anion radical (O2-â¢) etc. Existing studies have shown that changes in ROS levels are closely associated with the development of many diseases, such as inflammation, cancer, cardiovascular disease, and neurodegenerative damage. Small molecule fluorescent probes have been widely used in biology, pathology and medical diagnosis due to their advantages of noninvasive, high sensitivity and in vivo real-time detection. It is extremely important to better apply small-molecule fluorescent probes to detect ROS levels in organisms to achieve early diagnosis of diseases and assessment of therapeutic conditions. This work focuses on summarizing the representative applications of some fluorescent probes in ROS disease models in recent years. This article focuses on summarizing the construction methods of various ROS-related disease models, and classifying and analyzing the basic ideas and methods of fluorescent probes applied to disease models according to the characteristics of various diseases.
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Commercial diol chain extenders generally could only form two urethane bonds, while abundant hydrogen bonds were required to construct self-healing thermoplastic polyurethane elastomers (TPU). Herein, two diol chain extenders bis(2-hydroxyethyl) (1,3-pheny-lene-bis-(methylene)) dicarbamate (BDM) and bis(2-hydroxyethyl) (methylenebis(cyclohexane-4,1-diy-l)) dicarbamate (BDH), containing two carbamate groups were successfully synthesized through the ring-opening reaction of ethylene carbonate (EC) with 1,3-benzenedimetha-namine (MX-DA) and 4, 4'-diaminodicyclohexylmethane (HMDA). The two chain extenders were applied to successfully achieve both high strength and high self-healing ability. The BDM-1.7 and BDH-1.7 elastomers had high comprehensive self-healing efficiency (100%, 95%) after heated treatment at 60 °C, and exhibited exceptional comprehensive mechanical performances in tensile strength (20.6 ± 1.3 MPa, 37.1 ± 1.7 MPa), toughness (83.5 ± 2.0 MJ/m3, 118.8 ± 5.1 MJ/m3), puncture resistance (196.0 mJ, 626.0 mJ), and adhesion (4.6 MPa, 4.8 MPa). The peculiar mechanical and self-healing properties of TPUs originated from the coexisting short and long hard segments, strain-induced crystallization (SIC). The two elastomers with excellent properties could be applied to engineering-grade fields such as commercial sealants, adhesives, and so on.
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Reactive oxygen species (ROS) are an important component for maintaining normal physiological activities in organisms, and abnormal changes in their level are often accompanied by many diseases. As the two most representative components of ROS, HClO and H2O2 play vital roles in many physiological and pathological processes and are interdependent and mutually transformable. Although there is a lot of work that has specifically detected HClO or H2O2, there are few reports on the simultaneous differential detection of HClO and H2O2. Here, we report a ratio-based fluorescent probe capable of simultaneously distinguishing HClO and H2O2 based on making the best use of the untapped potential of coumarin derivatives. This probe was triumphantly put into use in the discriminative identification of HClO and H2O2 in aqueous media with high sensitivity and selectivity, and the probe was appropriate in a wide pH range. Furthermore, the imaging experiment for HClO and H2O2 in cells and zebrafish was eventually proven to be feasible. Importantly, this probe was qualified for monitoring the variation of HClO and H2O2 levels in organisms with alcoholic liver injury.
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Colorantes Fluorescentes , Ácido Hipocloroso , Animales , Colorantes Fluorescentes/análisis , Peróxido de Hidrógeno/análisis , Ácido Hipocloroso/análisis , Hígado/diagnóstico por imagen , Pez CebraRESUMEN
Liquid adhesive suffers from the emission of volatile organic compounds (VOCs) that have detrimental effects on human beings. Herein, an environmentally friendly glue containing a novel supramolecule dissolved in non-toxic ethanol is developed. Poly (ether amine) (PEA) and 3,4-dihydroxybenzaldehyde (dhba) is utilized to synthesize catechol-terminated PEA, and subsequent complexation by Fe3+ results in the supramolecular component (PEA-dhba-Fe3+). The Fourier transform infrared (FTIR) spectrum together with the UV-vis spectrum reveal the existence of quinone converted from catechol. Raman spectra prove the existence of a successful complex of catechol-terminated PEA with Fe3+. The tri-complex is found to be the predominant mode and can successfully form into clusters, serving as a physical cross-linking network. The PEA-dhba-Fe3+ exhibits strong adherence to metal substrates compared to polymeric substrates, with its shear strength reaching as high as 1.36 ± 0.14 MPa when the pH of the glue is adjusted to 8. The obvious improvement of adhesion originates from the formation of interfacial coordination bonds between quinone/catechol and metal atoms, as well as their cations, as revealed by X-ray photoelectron spectroscopy (XPS) and theoretical calculations. With consideration of its merits, including strong adhesion and the minor emission of VOCs compared to commercial epoxy and acrylic adhesives, this environmentally friendly supramolecular glue has a range of cutting-edge applications as an adhesive for metal substrates.
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The development of intrinsic self-healing elastomers with simultaneous high mechanical strength, toughness and room-temperature reparability remains a formidable challenge. Herein, we report a mechano-responsive strategy, known as strain induced crystallization, to address the above issue, whereby synthesized elastomers with unprecedented high mechanical performances are bestowed with room-temperature self-healing materials, achieving tensile strength, toughness and fracture energy values of 29.0 MPa, 121.8 MJ m-3 and 104.1 kJ m-2, respectively.
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Hypochlorite (ClO-), a type of reactive oxygen species (ROS), plays an essential role in complex biological systems. Real-time detection of the content and distribution of ClO- in cells or subcellular organelle is critically essential. In this paper, a lysosomal-targeted fluorescent probe, Cou-Lyso, was constructed for real-time detection of ClO- in a ratiometric manner, achieving high sensitivity with a low detection limit (0.58 µM). Upon reaction with ClO-, this probe was subjected to a significant fluorescence change from red emission (λmaxem = 610 nm) to green emission (λmaxem = 535 nm) with the ratio of I535 nm/I610 nm displaying a 76-fold enhancement from 0.04 to 3.03. The confocal imaging experiments for Cou-Lyso showed that this probe could detect ClO- in living cell and zebra fish. This probe has been successfully applied to stain lysosome and image lysosomal ClO- based on co-localization imaging experiments.
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Colorantes Fluorescentes , Ácido Hipocloroso , Animales , Cumarinas , Lisosomas , Fenotiazinas , Pez CebraRESUMEN
In this work, we presented a long-wavelength emission fluorescent probe DCM-Cou-SePh that can discriminatively detect glutathione (GSH) and hydrogen polysulfides (H2Sn, nâ¯>â¯1) from green and red emission channels, respectively. With the addition of GSH, probe DCM-Cou-SePh displayed green fluorescence emission (λex/emâ¯=â¯430/530â¯nm). In the presence of H2Sn, the probe exhibited a significant fluorescence enhancement in red channel (λex/emâ¯=â¯560/680â¯nm). We also demonstrated that this probe was suitable to quantitatively detect GSH and H2Sn with low detection limits (0.12⯵M for GSH, 0.19⯵M for H2Sn). Furthermore, DCM-Cou-SePh can be used for sensing endogenous GSH and H2Sn in living cells by dual-color fluorescence imaging.
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Silver ions (Ag+) are the most representative harmful ions found in polluted water and widely used in many industries; excessive ingestion of Ag+ in the human body may result in interaction with different metabolites in the human body and in aquatic microorganisms, leading to many diseases. Therefore, there is a great desire to develop good fluorescent probes for Ag+. Herein, a kind of mitochondrion-targeted fluorescent carbon dot was developed. These carbon dots exhibit 29.5% fluorescence quantum yield in water, good photostability and thermal stability. The as-fabricated carbon dots can quickly detect Ag+ in 100% water solution with good selectivity and anti-interference ability. Further, the carbon dots have been successfully applied to monitor Ag+ in living cells via the dual-channel method.
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Puntos Cuánticos , Plata , Carbono , Humanos , Iones , MitocondriasRESUMEN
As momentous reactive oxygen species (ROS), it is necessary to develop high-sensitivity and high-specificity fluorescent probes for tracking hypochlorite anion (ClO-) in environmental and biological systems. Herein, a kind of red luminescent carbon dots (NS-dots) was synthesized by one-step solvothermal method to detect ClO- in PBS buffer solution (VPBS:VEtOH = 100:1, pH = 7.4). The NS-dots has high sensitivity and low detection limit (13.3 µmol/L) for detecting ClO- with linear range from 6.7 × 10-5 mol/L to 26.7 × 10-5 mol/L. Using Rhodamine B (31% at 520 nm in water) as a reference, the NS-dots have a fluorescence quantum yield of 7.2%. Intracellular photostability, mitochondrial targeting properties and the fluorescence imaging towards intracellular ClO- were demonstrated.
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Colorantes Fluorescentes , Ácido Hipocloroso , Carbono , Fluorescencia , Humanos , MitocondriasRESUMEN
Metal ions and anions play significant roles in biological systems and industrial processes, therefore it is important to develop good fluorescent probes to detect metal ions and anions. Here, N,O-co-doped carbon quantum dots (CDs) that could detect Zn2+ via a ratiometric fluorescence method were fabricated. The reaction between the as-prepared CDs and zinc acetate gave the composite CDs-Zn, in which fluorescence changed ratiometrically upon addition of S2 O8 2- . With change in excitation light, the emission peaks of the CDs and CDs-Zn were kept fixed while intensity changed. CDs and CDs-Zn exhibited good photostability, thermal stability, selectivity, and strong anti-interference ability. In addition, CDs and CDs-Zn displayed low dark toxicity under physiological temperatures. Ratiometric fluorescence imaging of intracellular Zn2+ and S2 O8 2- was carried out in living HeLa cells for both of these probes. Compared with reported ratiometric fluorescent hybrid nanosensors based on organic dyes and inorganic nanomaterials, the as-prepared CDs and CDs-Zn had low toxicity, and were easy to synthesize.
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Carbono , Puntos Cuánticos , Colorantes Fluorescentes , Células HeLa , Humanos , Iones , Puntos Cuánticos/toxicidad , ZincRESUMEN
Conventional approaches to synthesize thermoplastic polyurethane (TPU) with excellent robustness are limited by a competing relationship between soft and hard segments for tuning mechanical properties in terms of chain flexibility and micro-phase separation. Herein, we present a facile and effective way of simultaneously improving the tensile strength, elongation, and toughness by constructing dynamic cross-linkages from metal-ligand interaction between Zn2+ and pyridine moiety in backbone of poly(urethane urea) (PUU) derived from 2,6-diaminopyridine and poly(propylene glycol). It was found that a Zn2+/pyridine ratio of 1:4 is the most effective for improving robustness. Specifically, tensile strength, elongation, and toughness could be remarkably increased to 16.0 MPa, 1286%, and 89.3 MJ/m3 with 226%, 29%, and 185% increments compared to uncomplexed PUU, respectively. Results from UV-vis, Fourier transform infrared spectroscopy (FTIR), cyclic tensile tests, and stress relaxation reveal that metal-ligand interaction significantly interferes with the hydrogen bonding of urea groups, thus leading to weakening of stiffness. Furthermore, half of vacant ligands enable dynamic complexation during stretching, which consequently ensures constant noncovalent cross-linkages for constraining mutual chain sliding, contributing to simultaneous improvement of tensile strength, elongation, and toughness. This work provides a promising approach for designing TPU with excellent robustness.
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Petroleum depletion and climate change have inspired research on bio-based polymers and CO2 capture. Tung-oil-based polyols were applied to partially replace polyether-type polyols from petroleum for sustainable polyurethane. Tung-oil-based polyurethane (TBPU), was prepared via a two-step polycondensation, that is, bulk prepolymerization and chain extension reaction. The graphene oxide (GO) was prepared via Hummer's method. Then, TBPU was composited with the GO at different ratios to form a TBPU/GO hybrid film. The GO/TBPU films were characterized by fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermal gravimetric analysis (TGA) and scanning electron microscope (SEM), followed by the measurement of mechanical properties and gas permeability. The results showed that the addition of tung-oil-based polyols enhanced the glass transition temperature and thermal stability of TBPU. The mechanical properties of the hybrid film were significantly improved, and the tensile strength and elongation at break were twice as high as those of the bulk TBPU film. When the GO content was higher than 2.0%, a brittle fracture appeared in the cross section of hybrid film. The increase of GO content in hybrid films improved the selectivity of CO2/N2 separation. When the GO content was higher than 0.35%, the resulting GO agglomeration constrained the gas separation and permeation properties.
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It is critical to develop probes for rapid, selective, and sensitive detection of the highly toxic hydrazine in both environmental and biological science. In this work, under mild condition, a novel colorimetric and off-on fluorescent probe was synthesized for rapid recognition of hydrazine with excellent selectivity over other various species including some biological species, metal ions and anions. The limit of quantification (LOQ) value was 1.5×10-4M-3.2×10-3M (colorimetric method) and 1.5×10-4M-3.2×10-3M (fluorescent method) with as low as detection limit of 46.2µM.
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Colorimetría/métodos , Colorantes Fluorescentes/química , Hidrazinas/análisis , Colorantes Fluorescentes/síntesis química , Hidrazinas/química , Soluciones , Espectrometría de FluorescenciaRESUMEN
It is crucial for cell physiology to keep the homeostasis of pH, and it is highly demanded yet challenging to develop luminescence resonance energy transfer (LRET)-based near-infrared (NIR) ratiometric luminescent sensor for the detection of pH fluctuation with NIR excitation. As promising energy donors for LRET, upconversion nanoparticles (UCNPs) have been widely used to fabricate nanosensors, but the relatively low LRET efficiency limits their application in bioassay. To improve the LRET efficiency, core/shell/shell structured ß-NaGdF4@NaYF4:Yb,Tm@NaYF4 UCNPs were prepared and decorated with hemicyanine dyes as an LRET-based NIR ratiometric luminescent pH fluctuation-nanosensor for the first time. The as-developed nanosensor not only exhibits good antidisturbance ability, but it also can reversibly sense pH and linearly sense pH in a range of 6.0-9.0 and 6.8-9.0 from absorption and upconversion emission spectra, respectively. In addition, the nanosensor displays low dark toxicity under physiological temperature, indicating good biocompatibility. Furthermore, live cell imaging results revealed that the sensor can selectively monitor pH fluctuation via ratiometric upconversion luminescence behavior.
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Carbocianinas/química , Transferencia Resonante de Energía de Fluorescencia/métodos , Nanopartículas del Metal/química , Células HeLa , Humanos , Concentración de Iones de Hidrógeno , Rayos Infrarrojos , Microscopía Confocal , Reproducibilidad de los ResultadosRESUMEN
A novel rhodamine and 8-hydroxyquinoline-based derivative was synthesized, which is shown to act as a colorimetric chemosensor for Fe(3+) in aqueous solution with high selectivity over various environmentally and biologically relevant metal ions and anions with a distinct color change from colorless to pink in very fast response time (<1 min). Fe(3+) can be detected quantitatively in the concentration range from 6.7 to 16 µM and the detection limit (LOD) on UV-vis response of the sensor can be as low as 15 nM. The 'in situ' prepared Fe(3+) complex (1â Fe) showed high selectivity toward PPi against many common anions, and sensitivity (the LOD can be as low as 71 nM). In addition, both the chemosensor and the 'in situ' prepared Fe(3+) complex are reusable for the detection of Fe(3+) and PPi respectively.
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In this study, we discover unexpectedly that simple reaction of AgNO3 with oleic acid (OA) without solvent and surfactant could generate alkyl free radical which can catalyze double-bond polymerization of OA to form 1D polymeric oleic acid (POA) chain. In certain conditions, these POA chains circumvolute tightly each other to form microspheres and micro-plates in which monodisperse 4-5 nm Ag nanoparticles (NPs) were absorbed. It has been revealed that alkyl free radical generated during the redox reaction of carboxyl group of OA with Ag(+) at relative low temperature. Then, the alkyl free radical catalyzed the double-bond polymerization of OA when the reaction temperature was further increased. Different from commonly-seen hydrophobic nanoparticles prepared in oleic acid-based microemulsion system, the nanocomposites cannot dispersed in n-hexane and could dispersed in ethanol and THF. The unusual dispersion behavior has been explained in terms of their structure and polarity of POA chain. The method combines the nucleation of Ag nanoparticles and the polymerization of monomer in a facile one-pot reaction, which provides a novel way for metal-polymer microsphere nanocomposite with low-cost, easy-operation and high-yield.
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Previous reports of fluorescent sensors for alcohols based on charge-transfer character of their excited state are based on mono-, di-, and tetra-phosphonate cavitands, which are capable of selecting analytes through shape/size selection and various specific H-bonding, CH-π, and cation-dipole interactions. To contrast, color changes based on absorption properties of the ground state are more suitable for direct observation with the naked eye. Three sensitive and selective colorimetric sensors for C1-C4 alcohols have been developed on the basis of alcohol-mediated ground-state intramolecular proton transfer. Reverse proton transfer induced by water achieves a fully reversible reaction. In addition, the solvent color indicates alcohol concentration.