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The efficient capture and monitor of radioactive iodine are crucial for managing radioactive nuclear waste and protecting human health. Herein, three metal–organic coordination compound‐mediated supramolecular organic frameworks (MSOFs) are reported with distinct electron‐rich structures for efficient iodine capture with fluorescence response. The electron‐rich adsorption sites play crucial roles for electron‐deficient iodine capture via charge transfer interactions, where π donors contribute greater than nitrogen heteroatom. Among three MSOFs, MSOF‐3 with the maximum numbers of electron‐rich π donors exhibited the highest iodine uptake capacity (3.70 g mmol−1). Prominently, the charge transfer interactions between iodine and MSOFs result in distinct fluorescence response during iodine uptake, establishing a real‐time fluorescence monitoring system. To facilitate the personal health protection toward practical application, a mask with high iodine removal efficiency (99.1%) and real‐time fluorescence response is successfully developed. This study underscores the great promise of electron‐rich fluorescent MSOFs for capture and sensing of radioactive iodine, offering substantial prospects for the advance of protective equipment in the nuclear industry. [ABSTRACT FROM AUTHOR]

Heavy metals, particularly mercury, rank as some of the most hazardous systemic toxicants known to cause multiple organ damage, even at lower levels of exposure. Its detection in the environment and in the live cells is an actual task. Here, we engineered a novel genetically encoded fluorescent NMT indicator for mercury ions by inserting the metallothionein II domain from rat liver into the bright green-yellow fluorescent protein mNeonGreen, followed by directed molecular evolution of the resulting sensor prototype in bacteria. In solution, the NMT indicator was 1.7-fold brighter than the standard eGFP fluorescent protein and responded to the addition of even 10−18-10−19 M mercury ions by quenching fluorescence with a 5-fold fluorescence response and extremely high affinity to mercury ions characterized by the Kd value of 0.50 ± 0.05 aM. We also characterized the selectivity of the NMT indicator to other metal cations. In cultured mammalian cells, the NMT indicator detected even an extracellular concentration of 0.1 fM mercury ions and achieved a 5.9-fold change in ΔF/F fluorescence intensity.

Abstract In supramolecular chemistry, the pursuit of highly efficient molecular recognition systems holds paramount significance. This study introduces new [2.2]paracyclophanes (PCP) as exceptional guest molecules for cucurbit[8]uril (CB8). This well‐matched host‐guest interaction is marked by ultra‐high binding affinities (Ka up to 1015 M−1 in water) accompanied by unprecedented exothermic contributions (ΔH up to −20.6 kcal mol−1) observed in CB8 binding, rivaling the exceptional affinities of cucurbit[7]uril (CB7), which has until now been recognized as the gold standard for high‐affinity binding in water. The PCPs demonstrate an excellent fit within the CB8 cavity without structural deformation of the host. Our research methodology incorporates organic synthesis, NMR, fluorescence titration, and isothermal titration calorimetry (ITC) experiments, as well as quantum mechanical simulations, to systematically examine the binding characteristics of fluorescent mono‐ and dicationic PCP guests within the CB8 cavity. This study not only corroborates but also critically reevaluates certain aspects of the “high‐energy water release model” for cucurbit[n]uril systems. Furthermore, the ease of modifying PCP compounds, combined with their superior water solubility compared to di‐ and triamantanes, and their characteristic fluorescent response in forming and disassembling host‐guest complexes, elevates PCPs as promising candidates for the creation of advanced supramolecular CB8‐functional materials and sensing assays.

Polyureas (PUs) have already found wide practical applications, and various methods of their synthesis have been reported. In this manuscript, we wished to report the very first mechanochemical approach towards aromatic PUs via reactions between isomeric 2,2′-, 3,3′-, and 4,4′-diaminobiphenyls and triphosgene under solvent-free conditions following ball-milling. By using this synthetic approach, both PUs and azomethine-capped Pus were obtained. The fluorescence response of the above-mentioned PUs towards various anions in solutions were studied and selective fluorescence responses towards the hydroxyl and fluoride anions were observed. [ABSTRACT FROM AUTHOR]

Hypoxia, defined as a local insufficiency in the oxygen level, is one of the typical phenomena found in spinal cord injury and solid tumors. Deficiency in the oxygen offers a reductive environment and results in the conversion of nitro groups to amino groups, which can be utilized in the initiation of stimuli-sensitive cascade reactions. A novel hypoxia-sensitive material was synthesized as composed of a hypoxia-activatable trigger unit and two pyrene dyes bound via carbamate linkers, and it produced fluorescence and ultrasound signals. The material was successfully produced through seven synthetic steps and characterized via1H-NMR and UV-vis absorption analysis. The material maintained its chemical structure at the normoxic state, but underwent degradation into free pyrene dyes, activated trigger units, and carbon dioxides by cascade reactions under the reductive hypoxic condition. Accompanied by the material decomposition, remarkably rapid recovery of the quenched fluorescence was observed within 3 min, and its intensity was completely saturated after 15 min. Notably, the fluorescence intensity from the degraded material was 9.2-fold stronger than that from the same concentration of native pyrene dyes because both the activated trigger unit and free pyrene exhibited bright fluorescence emission. Moreover, the carbon dioxide generated during the degradation of the material formed nanobubbles in the media, increasing the ultrasound contrast by 1.2-fold over the background. In summary, the synthesized material was found to produce a potent, hypoxia-sensitive system to visualize the hypoxic condition in terms of fluorescence and ultrasound responses. [ABSTRACT FROM AUTHOR]

A practical synthesis of nonsymmetrical thiophene‐fused aromatic systems has been developed that was inspired by the biodegradation of benzothiophene. For the first time, the photophysical properties of a series of π‐conjugated benzo[b]naphtho[1,2‐d]thiophene (BNT) sulfoxides were explored both in solution and in the solid state. The excellent fluorescence characteristics enable various applications of these compounds. [ABSTRACT FROM AUTHOR]

Acenaphthene imidazole ligand (AIMP) reacted with zinc acetate for the synthesis of Zn-AIMP complex which was used to detect pyrophosphate (PPi) ions in the environment as well as biotic systems based on the ligand cleavage method. The designed Zn−AIMP probe has greater fluorescence quenching response to PPi ions compared to other competitive ions and biothiols. Zn−AIMP probe shows the detection limit of 6 μM in dimethyl sulfoxide with the binding constant (Kb) value of 1.02 × 104 M–1. Moreover, the probe possesses detection ability in the pH range from 4 to 10, which is also an optimum range for any biotic system. [ABSTRACT FROM AUTHOR]

• This MHOF shows a 4-fold interpenetrated three-dimensional (3D) network structure. • 1 has excellent fluorescence properties and can be used as fluorescent chemical sensor. • The photoinduced electron transfer (PET) and fluorescence resonance energy transfer (FRET) are two potential quenching processes. For health, environmental and safety reasons, it is necessary to conduct highly sensitive detection of organic contaminant antibiotics (sulfathiazole) and nitro explosive drugs (o-nitroaniline) in water. In this work, metal-hydrogen bonded organic framework (MHOF), {[Co(Ad) 2 (H 2 O) 4 ]·(H 2 L)·2.5H 2 O} n (1), was synthesized by a one-pot hydrothermal method with 2,6-bis(3,5-dicarboxyphenoxy) pyridine (H 4 L) and adenine (Ad). This MHOF shows a 4-fold interpenetrated three-dimensional (3D) network structure. Importantly, 1 has excellent fluorescence properties and can be used as fluorescent chemical sensor to detect sulfathiazole (STZ) and 2-nitroanilin (2-NA) with limit of detection (LOD) 203 ppb and 6.8 ppb, respectively. By UV-vis absorption/emission spectroscopic measurements and DFT calculations, it is found that photoinduced electron transfer (PET) and fluorescence resonance energy transfer (FRET) are two potential quenching processes. This is the first report of metal-hydrogen bond organic frameworks (MHOFs) as a promising new fluorescent chemical sensor for the detection of organic pollutants in water. A four-layer interpenetrating metal-hydrogen bonded organic framework (MHOF) {[Co(Ad) 2 (H 2 O) 4 ]·(H 2 L)·2.5H 2 O} n was synthesized under solvothermal conditions, which has excellent fluorescence characteristics and can be used as a fluorescent chemical sensor for the detection of sulfathiazole (STZ) and 2-nitroaniline (2-NA) with detection limits of 203 ppb and 6.8 ppb, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • An SPME biosensor modified with special double-stranded DNA structures was developed. • No fluorescent material modification on the nucleic acid was needed for the sensor. • The sensitivity was significantly enhanced by the thioflain T and G-quadruplex dimer. Streptomycin (STR), an aminoglycoside antibiotic with the potential to persist in honey and other food products, may induce allergy, toxicity and antibiotic resistance in humans. In this study, we developed a solid-phase microextraction (SPME) biosensor based on a quartz rod that was modified with double-stranded DNA structures consisting of partially complementary G-rich base DNA strand and STR aptamer. The STR isolated by SPME initially bound to the aptamer. Then the remaining double-stranded DNA structures were cleaved by the Nt.BstNBI enzyme, resulting in release of G-quadruplex dimers. The latter formed a complex with thioflain T fluorescent dye, resulting in an amplified fluorescence response. The method exhibited high sensitivity (a limit of detection of 10.84 pM), wide linear range (0.05 nM ∼ 500 nM (with determination coefficient > 0.99)), and simple operation, making it suitable and convenient for STR detection. Successful STR determination in genuine honey samples was demonstrated. [ABSTRACT FROM AUTHOR]

Industrial waste acidic gases are huge hazards to the environment and human health, so a material that can detect and remove them is needed. In this paper, CM chitosan-Eu3+ fluorescence aerogel was prepared via a green method by combining the carboxymethyl chitosan biomass polymer with Eu3+ ions, the structure and properties of this aerogel were characterized by SEM, TG, and stress-strain curves. The coordination of Eu3+ ions and carboxymethyl chitosan was analyzed with XPS and the difference in luminescence intensity of aerogel prepared at different pH values was analyzed. The monitoring of the aerogels revealed different responses to different acidic gases, and the fluorescence intensity of the aerogel showed a linear decrease with the adsorbed hydrogen chloride gas (HCl), while acetic acid gas (HAc) enhanced fluorescence. The adsorption system of the CM chitosan-Eu3+ aerogel was simulated using pseudo-second-order kinetics, which showed that the maximum adsorption capacity of HCl is 9.16 mmol/g. The different response mechanisms of HCl and HAc gas were analyzed with FT-IR, fluorescence lifetime imaging and Judd-Ofelt theory. This fluorescence aerogel was found to have potential applications in ensuring industrial production safety. • Fluorescence aerogels were prepared by adjusting the pH of CMCh and Eu3+ ions solution. • The involvement of amino, hydroxyl, carboxyl and ether bond in CMCh in the coordination of Eu3+ ion was well demonstrated by XPS. • The fluorescence of CMCh-Eu3+ aerogel displayed a segmented linear quenching in HCl gas, while enhanced in HAc gas. • The fluorescence response of aerogels to HCl and HAc gas was proved with FTIR, fluorescence lifetime and Judd-Ofelt theory. [ABSTRACT FROM AUTHOR]

Thermosetting plastics exhibit remarkable mechanical properties and high corrosion resistance, yet the permanent covalent crosslinked network renders these materials challenging for reshaping and recycling. In this study, a high-performance polymer film (EI 25 -TAD 5 -Mg) was synthesized by combining click chemistry and cation-π interactions. The internal network of the material was selectively constructed through flexible triazolinedione (TAD) and indole via a click reaction. Cation-π interactions were established between Mg 2+ and electron-rich indole units, leading to network contraction and reinforcement. Dynamic non-covalent interactions improved the covalent crosslinked network, and the reversible dissociation of cation-π interactions during loading provided effective energy dissipation. Finally, the epoxy resin exhibited excellent mechanical properties (tensile strength of 91.2 MPa) and latent dynamic behavior. Additionally, the thermal reversibility of the C-N click reaction and dynamic cation-π interaction endowed the material with processability and recyclability. This strategy holds potential value in the field of modifying covalent thermosetting materials.

Heavy metals, particularly mercury, rank as some of the most hazardous systemic toxicants known to cause multiple organ damage, even at lower levels of exposure. Its detection in the environment and in the live cells is an actual task. Here, we engineered a novel genetically encoded fluorescent NMT indicator for mercury ions by inserting the metallothionein II domain from rat liver into the bright green-yellow fluorescent protein mNeonGreen, followed by directed molecular evolution of the resulting sensor prototype in bacteria. In solution, the NMT indicator was 1.7-fold brighter than the standard eGFP fluorescent protein and responded to the addition of even 10 -18 -10 -19  M mercury ions by quenching fluorescence with a 5-fold fluorescence response and extremely high affinity to mercury ions characterized by the K d value of 0.50 ± 0.05 aM. We also characterized the selectivity of the NMT indicator to other metal cations. In cultured mammalian cells, the NMT indicator detected even an extracellular concentration of 0.1 fM mercury ions and achieved a 5.9-fold change in ΔF/F fluorescence intensity., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Histidine Polypeptide-Hybridized Nanoscale Metal–Organic Framework (fH12/ZIF-8) can be produced effectively in water at room temperature without using any additives. The fluorescein label also provides a useful method to quantify the extent to which the anti-cancer drug doxorubicin (DOX) is loaded into or released from the resulting MOFs. In vitro studies have shown that fH12/ZIF-8 has the useful property of dissolving and controlled rates at low pH. It ruptured fastest in PBS buffer solution with pH 6.3, and the release rate reached 50% at 4 h. Furthermore, it showed that the addition of histidine polypeptides increases uptake by HepG-2 cells. This study integrates drug loading and detecting aspects into a single theranostic platform by a simple and efficient strategy, opening a new route for the construction of advanced drug delivery systems.

[Display omitted] • Fluorescent diosmetin probe was carried out according to nitrogen-doped carbon dots (N-CQDs). • The N-CQDs exhibited a low detection limit of 0.049 μM for the determination of diosmetin. • The usability of N-CQDs for the determination of diosmetin in real samples was carried out. • The fluorescence quenching mechanism was the inner filter effect. In this paper, a single signal fluorescent sensor of nitrogen-doped carbon dots (N-CQDs) was established for the micro-determination of diosmetin. In this determination platform, the as-developed N-CQDs with yellow fluorescence were prepared through a facile hydrothermal method with p-phenylenediamine and ascorbic acid as the precursors containing nitrogen and carbon. The as-developed N-CQDs had a classical surface structure and surprising fluorescence stability. The maximum excitation and emission peaks were located at 372 and 528 nm, respectively. Under the optimal sensing conditions, the as-prepared N-CQDs held preeminent immunity towards possible interfering substances. The determination platform's fluorescence intensity was quenched because of the static quenching and inner filter effect. The fluorescence weakening changes displayed an attractive linear relationship with diosmetin in range of 0.5–150 μM, and the linear equation was ln(F 0 /F) = 0.014[Q]–0.055 with the R2 of 0.9975 and the detection limit of 0.049 μM. The determination platform could be applied for the trace detection of diosmetin in river water and bovine serum samples. The corresponding recovery rate was 94.8 %–108.8 %, exhibiting that it was a facile and efficient fluorescence sensing strategy. [ABSTRACT FROM AUTHOR]

In this study, we designed and synthesized metalloporphyrin derivatives (with Ni and Zn) specifically intended for the fluorescence detection of nicotine in aqueous solutions. Our results showcased a notable selectivity for nicotine over other naturally occurring food toxins, exhibiting an exceptional sensitivity with a limit of detection as low as 7.2 nM. Through mechanistic investigations ( 1 H NMR, FT-IR, etc.), we elucidated the binding mechanism, revealing the specific interaction between the pyridine ring of nicotine and the metal center, while the N atom pyrrolidine unit engaged in the hydrogen bonding with the side chain of the porphyrin ring. Notably, we observed that the nature of the metal center dictated the extent of interaction with nicotine; particularly, Zn-porphyrin demonstrated a superior response compared to Ni-porphyrin. Furthermore, we performed the quantitative estimation of nicotine in commercially available tobacco products. Additionally, we conducted the antibacterial ( Staphylococcus aureus and Escherichia coli ) and antifungal ( Candida albicans ) activities of the porphyrin derivatives.

Based on the design of the fluorescent site of a fluorescent probe, we have created a unique system that changes its twisting response to sugar. Two probes were synthesized, in which phenylboronic acid and two kinds of aromatic fluorescent site (pyrene or anthracene) were conjugated by an amide bond. In the fluorescence measurement of pyrene-type probe 1, dimer fluorescence was observed at high pH. In induced circular dichroism (ICD) experiments, a response was observed only in the presence of glucose and γ-cyclodextrin, and no response was seen with fructose. On the other hand, in the fluorescence measurement of anthracene-type probe 2, dimer fluorescence was observed in the presence of both glucose and galactose, and the fluorescence was different from the case of fructose. When the ICD spectra of these inclusion complexes were measured, an inversion of the Cotton effect, which indicates a change in the twisted structure, was observed in galactose and glucose. These differences in response to monosaccharides may originate in the interaction between the fluorescent site and the cyclodextrin cavity. [ABSTRACT FROM AUTHOR]

The release of hazardous NH 3 toxic gas poses a significant threat to both the environment and human health, necessitating the development of materials capable of detecting NH 3. This research focuses on the design of a fluorescent gel derived from the peeling-off reaction of Artemisia sphaerocephala Krasch. gum (ASKG). The variations in fluorescence intensity were examined for gels produced under different conditions of pH and adsorption capacity of NH 3. The fluorescence response mechanism concerning NH 3 and pH value was investigated through analysis of fluorescent lifetime, FT-IR, X-ray XPS, and GPC. Dextran was employed to validate this mechanism. The ASKG gel exhibited a rapid response to NH 3 gas, and the fluorescence intensity demonstrated a linear correlation with the cumulative adsorption of NH 3 gas. Pseudo-first-order kinetics was applied to analyze the adsorption system of the ASKG gel, revealing a maximum adsorption capacity of 0.03476 g/g for NH 3. The practical application of the ASKG gel was demonstrated through a fish spoilage experiment. [Display omitted] • ASKG gels were prepared based on peeling-off reaction which showed fluorescence under alkaline condition. • The fluorescence of ASKG is from the π-π stacking of the carbonyl and carboxyl formed by the peeling-off reaction. • ASKG gel revealed linear relationship between NH 3 adsorption and fluorescence and can be used in fish freshness detection. [ABSTRACT FROM AUTHOR]

Antioxidant carbon dots (ACDs) with high quantum yield were designed for the effective detection of bleomycin (BLM) with the presence of ferrous ions (Fe2+) ascribed to the specific fluorescence response of ACDs to hydroxyl radical (OH). [Display omitted] • Antioxidant carbon dots (ACDs) with high quantum yield were prepared. • ACDs exhibit enhanced fluorescence ability with the surface rich in amino, hydroxyl and carboxyl groups. • ACDs have selective and sensitive fluorescence response to ·OH through dynamic quenching effect. • The interaction of bleomycin and Fe2+ with the generation of ·OH was applied to detect bleomycin using ACDs as probe. In this work, antioxidant carbon dots (ACDs) with high quantum yield (63.98%) were developed through a one-step strategy using citric acid, ethylenediamine, and L-arginine as sources. The ACDs demonstrated excellent in vitro antioxidant activity. Additionally, ACDs displayed a unique fluorescence response to hydroxyl radical (OH). Leveraging this distinctive feature, a selective and sensitive fluorescence-based sensor was developed for detecting bleomycin (BLM) in the presence of ferrous ions (Fe2+). The studies on the oxidizing properties and dynamic quenching mechanism of ACDs by OH suggested that OH reduced the contents of the amino and hydroxyl groups of ACDs, leading to a decreased electron cloud density of ACDs for dynamic quenching of ACDs. Under optimally refined conditions, the detection limit of this strategy for BLM was 0.58 μg/mL, with a linear range spanning from 1 to 24 μg/mL when employing ACDs as the probe. This fluorescence sensing strategy provides a promising method for the detection of BLM in clinical samples. [ABSTRACT FROM AUTHOR]

• The novel functional microgels (PNI-MSPC) were synthesized, which exhibited thermo-sensitivity, redox actuatable size and fluorescence. • The PNI-MSPC microgels can be used as the fluorescent sensor for ultrasensitive and selective detection of MnO 4 − anions in aqueous solution. • The limit of detection for MnO 4 − anions was about 25 nM with a fast response time of 5 min and a linear concentration range of 0–50 μM. The novel functional microgels, namely PNI-MSPC microgels, were fabricated via surfactant free emulsion polymerization (SFEP) by using N -isopropylacrylamide (NIPAm) as the monomer and a home-designed dichlorinated 1,1′-di[4-(vinyl)benzyl]-4,4′-pyridinium salt (MSPC2+.2Cl−) as the cross-linker. The PNI-MSPC microgels exhibited not only thermo-sensitivity but also redox actuatable hydrodynamic diameter and fluorescence properties. The PNI-MSPC microgels were successfully applied as the fluorescent sensor for ultrasensitive and selective detection of trace MnO 4 - anions in aqueous solutions. The presence of MnO 4 - anions led to the significant fluorescence quenching of the PNI-MSPC microgels with a fast response time of 5 min. The limit of detection (D L) for MnO 4 - anions can reach 25 nM with a linear concentration range of 0–50 μM. The co-existence of 16 other species of anions or 17 species of metal ions did not interfere with the detection of trace MnO 4 - anions in aqueous solutions. The potential applications of the PNI-MSPC microgels for sensing trace MnO 4 - anions in real world samples were also validated. [ABSTRACT FROM AUTHOR]

Abstract Two fluoranthene derivatives with "propeller" structure, named as 7,8,9,10-tetraphenylfluoranthene (TPFA) and 3-phenoxy-7,8,9,10-tetraphenyl fluoranthene (PO - TPFA), were designed and synthesized by introducing outer phenyl and phenoxy substituents to fluoranthene. Given the steric hindrance of this unique structure, both organic dyes exhibited similar fluorescence spectra and strong fluorescence emission from the solution to the film state. The introduction of a phenoxy group showed obvious influence to the molecular optical properties of fluoranthene. Density functional theory calculations were further conducted to verify this finding. Both dyes were used as fluorescent probes and exhibited and sensitive fluorescence response to nitroaromatic explosives and highly selectivity to picric acid. Furthermore, PO - TPFA exhibited better detection performance to nitroaromatic explosives than TPFA. This work can serve as a guide for molecular fluorescence design because these dyes possess excellent fluorescence in solution and film states and can be used for the sensitive fluorescence detection of nitroaromatic explosives. Graphical Abstract Unlabelled Image Highlights • Two fluoranthene-based dyes with unique structure were synthesized. • Two dyes both have greatly twisted structure and exhibit excellent fluorescence in film. • The geometrical structures, frontier orbitals and energy levels were explored by DFT calculation. • Two dyes both shows high detection sensitivity for nitroaromatic explosives. • The phenoxy substituent could effectively improve the detection sensitivity. [ABSTRACT FROM AUTHOR]

Information encryption technologies are very important for security, health, commodity, and communications, etc. Novel information encryption mechanisms and materials are desired to achieve multimode and reprogrammable encryption. Here, a supramolecular strategy is demonstrated to achieve multimodal, erasable, reprogrammable, and reusable information encryption by reversibly modulating fluorescence. A butyl-naphthalimide with flexible ethylenediamine functionalized β-cyclodextrin (N-CD) is utilized as a fluorescent responsive ink for printing or patterning information on polymer brushes with dangling adamantane group grafted on responsive hydrogels. The photoluminescent naphthalimide moiety is bonded to β-CD and entrapped in the cavity. Its fluorescence is highly weakened in β-CD cavity and recovers after being expelled from the cavity by a competing guest molecule to emit bright green photoluminescence under UV. Experiments and theoretical calculations suggest π-π stacking and ICT as the primary mechanism for the naphthalimides assembly and fluorescence, which can be quenched through insertion of conjugated molecules and recover by removing the insert. Such reversible quenching and recovering are used to achieve repeated writing, erasing, and re-writing of information. Supramolecular recognition and hydrogel shape memory are further combined to achieve reversible dual-encryption. This study provides a novel strategy to develop smart materials with improved information security for broad applications., (© 2023 Wiley-VCH GmbH.)

A new Porous Organic Polymer (POP), termed CTF-PTZ , was synthesized through polymerization of 10-methyl-10H-phenothiazine-3,7-dicarbonitrile in the presence of trifluoromethanesulfonic acid catalyst. Owing to the richness of heteroatoms such as N and S atoms in its molecular structure, the fluorescence response of CTF-PTZ to metal ions was studied, and it was found that CTF-PTZ had a specific fluorescence response to Hg2+. Thus, high selectivity in fluorescence responsiveness to Hg2+ of CTF-PTZ was revealed and the detection limit of it was up to be 2.09 ​× ​10−7 moL·L−1, which was found by fluorescence spectroscopy titration and fluorescence competition experiments. We successfully demonstrated that the fluorescence responsive POP material provides the promising potential for Hg2+ detection. The TOC figure means that the fluorescence intensity of the CTF-PTZ in DOX solution decreases with the increase of mercury ion concentration, and can be directly observed with naked eye. To visually display the internal structure of CTF-PTZ, we also include its molecular structure. After that, the detection limit of mercury ions was calculated to be 2.09 ​× ​10−7 ​mol ​L−1 ​by titration experiment. [Display omitted] • A novel phenothiazine-based porous organic polymer (CTF-PTZ) was successfully prepared. • Fluorescence-selective polymer was synthesized by using low-cost materials under mild conditions. • CTF-PTZ has a specific fluorescence response to Hg2+ and the detection limit of it was up to be 2.09 ​× ​10−7 moL·L−1. [ABSTRACT FROM AUTHOR]

[Display omitted] • Diaxial complex of Sn(IV)-porphyrin with hydroxyphenyl-BODIPY was obtained. • The triad exhibits a high sensitivity of fluorescence to an acidity and viscosity of medium. • A photoactive material with high photoresistance and antibacterial activity has been developed. A triad of two 1,3,5,7-tetramethyl-8-(4-hydroxyphenyl)BODIPY ligands (BODIPY) axially linked to Sn(IV)-octaethylporphyrin [Sn(BODIPY) 2 OEtP] is synthesized. The structure of the triad is optimized by quantum chemical calculations and confirmed by a combination of physicochemical methods. The spectral luminescent properties of the triad and its components in DMF solution are studied. Using a model system of the DMF-glycerol binary solvent, the sensitivity of the photophysical characteristics of the triad to the concentration-dependent viscosity of the solution, as well as to the addition of acids and alkalis, is studied. Sn(BODIPY) 2 OEtP photoexcitation leading to photoinduced energy transfer from donor fragments of BODIPY to the porphyrinate acceptor is observed. As a result, upon excitation of the triad at λ ex = 490 nm both BODIPY fluorescence and porphyrin fluorescence are recorded. When the triad is excited at λ ex = 400 nm, the fluorescence of the porphyrin increases compared to the initial Sn(IV)-octaethylpophyrin. This energy transfer, which depends on both the mobility of the medium and its acidity, provides the Sn(BODIPY) 2 OEtPtriad with the properties of a molecular rotor, a pH indicator and very high photostability (resistance to photobleaching), as well as antibacterial activity against the Staphylococcusaureus ATCC strain. [ABSTRACT FROM AUTHOR]

A novel bovine serum albumin (BSA) surface imprinted polymer based on ZnO rods was synthesized by surface grafting copolymerization. It exhibited an excellent recognition performance to bovine serum albumin. The adsorption capacity and imprinting factor of bovine serum albumin could reach 89.27 mg/g and 2.35, respectively. Furthermore, the fluorescence property of ZnO was used for tracing the process of protein imprinting and it implied the excellent optical sensing property of this material. More importantly, the hypothesis that the surface charge of carrier could affect the imprinting process was confirmed. That is, ZnO with positive surface charge could not only improve the recognition specificity of binding sites to template proteins (pI < 7), but also deteriorate the bindings between sites and non-template proteins (pI > 7). It was also important that the reusability of ZnO@BSA molecularly imprinted polymers was satisfactory. This implied that the poor mechanical/chemical stability of traditional zinc oxide sensors could be solved by the introduction of surface grafting copolymerization. These results revealed that the ZnO@BSA molecularly imprinted polymers are a promising optical/electrochemical sensor element. [ABSTRACT FROM AUTHOR]

Poly[1-phenyl-2-(p-trimethylsilyl)phenylacetylene] (PTMSDPA) with microporous and intramolecular stack structures in the bulk solid state can be used as a fluorescent water sensor for on-line real-time monitoring. A solubility parameter ( δ) of PTMSDPA is estimated from the degree of swelling and solvation of the polymer in various organic solvents. When the PTMSDPA film is immersed in organic solvents with a range of δ values, the fluorescence (FL) intensity increases significantly due to swelling, whereas the FL intensity decreases gradually upon the addition of water in the solvents due to deswelling. The FL decreasing ratios are quite different according to the solvents. The hydrogen-bonding strength of the solvents toward water plays a key role in determining the FL responsivity of the polymer. The FL response is very specific to water in organic solvents. The PTMSDPA film responds quickly to water within several seconds. A fluidic channel of which the inner wall is coated with PTMSDPA is fabricated to demonstrate the on-line, real-time monitoring of water in flowing solvents. The development of more facile and convenient devices, such as microfluidic lab-on-chip and optode sensors, using PTMSDPA as an active layer will advance practical applications. [ABSTRACT FROM AUTHOR]

Abstract: Trace Cu2+ ions in aqueous solution were detected with ultra-sensitivity and excellent selectivity by using CdSe quantum dots (QDs) with enhanced fluorescence properties as fluorescent reporters. CdSe QDs were first synthesized by using aqueous route with 3-mercaptopropionic acid (3-MPA) as capping agent. By further thermal-annealing the as-prepared 3-MPA capped CdSe QDs in the presence of imidazole (IM) under nitrogen atmosphere at 70°C, the fluorescence quantum yields of CdSe QDs in aqueous solution could be dramatically enhanced to be ∼10.9%. These CdSe QDs with enhanced fluorescence exhibited fast fluorescence response (within 1min), ultra-sensitivity and excellent selectivity toward Cu2+ ions over other metal ions in aqueous solution. The Cu2+-induced aggregation of CdSe QDs led to the significant fluorescence quenching of the CdSe QDs. The limit of detection (LOD) calculated for Cu2+ could reach as low as 0.13–0.16ppb (2.0–2.5nM). The co-existence of other metal ions did not interfere with the sensing of trace Cu2+ ions in aqueous solution. [Copyright &y& Elsevier]

Clinicians require simple, and cost-effective diagnostic tools for the quantitative determination of amino acids in physiological fluids for the detection of metabolic disorder diseases. Besides, amino acids also act as biological markers for different types of cancers and cardiovascular diseases. Herein, we applied an in-silico based approach to identify potential amino acid-responsive genetic regulatory elements for the detection of metabolic disorders in humans. Identified sequences were further transcriptionally fused with GFP, thus generating an optical readout in response to their cognate targets. Screening of genetic regulatory elements led us to discover two promoter elements (pmetE::GFP and ptrpL::GFP) that showed a significant change in the fluorescence response to homocysteine and tryptophan, respectively. The developed biosensors respond specifically and sensitively with a limit of detection of 3.8 μM and 3 μM for homocysteine and tryptophan, respectively. Furthermore, the clinical utility of this assay was demonstrated by employing it to identify homocystinuria and tryptophanuria diseases through the quantification of homocysteine and tryptophan in plasma and urine samples within 5 h. The precision and accuracy of the biosensors for disease diagnosis were well within an acceptable range. The general strategy used in this system can be expanded to screen different genetic regulatory elements present in other gram-negative and gram-positive bacteria for the detection of metabolic disorders. • In-silico based screening of promoters for the detection of metabolic disorders. • metE and trpL were identified for the detection of homocystinuria and tryptophanuria. • Biosensors specifically detect cognate targets within 5 h without showing interference. • Accuracy and precision of the developed sensors were all within the acceptable range. • The proposed method is sensitive and cost-effective than extant methods. [ABSTRACT FROM AUTHOR]

Highlights: [•] A magneto immunoassay for the detection of anti-transglutaminase antibodies (ATG2). [•] The ATG2 were captured by transglutaminase enzyme immobilized on magnetic beads. [•] The fluorescent response of the revelation system was related to ATG2. [•] The novel assay can discriminate correctly between celiac and non-celiac patients. [•] The novel assay is four times more sensitive than the commercial ELISA assay. [ABSTRACT FROM AUTHOR]

Abstract: A series of novel tetrahedral silicon-centered imidazolyl derivatives, Bis(4-(imidazol-1-yl)phenyl)dimethylsilane (1), Tri(4-(imidazol-1-yl)phenyl)methyl silane (2), Bis(4-(imidazol-1-yl)phenyl)diphenylsilane (3), Tri(4-(imidazol-1-yl)phenyl)phenylsilane (4), [Bis(4-(imidazol-1-yl)phenyl)](4-bromophenyl)phenylsilane (5) and [Tri(4-(imidazol-1-yl)phenyl)](4-bromophenyl)silane (6) have been synthesized and characterized by FTIR, 1H NMR, 13C NMR and mass spectroscopy. They all display high thermal stability, are fluorescent with emission in the region of violet to blue, and possess large HOMO-LUMO energy gaps ranging from 4.9585 to 5.1879 eV, which could be potentially used as blue emitters or hole blocking materials in OLEDs. Moreover, the metal ion titrations based on Ag (I) and compounds 1–4 reveal that these ligands show distinguishable fluorescence response with increasing of Ag (I) ions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Trans -diaxial complex of Sn(IV)-octaethylporphyrin with fluorescein was obtained. • The triad exhibits a high sensitivity of fluorescence and photostability to molecule ionization. • Photoactive porphyrin-fluorescein material to control the acidity of medium was designed. Trans -diaxial complex of Sn(IV)-2,3,7,8,12,13,17,18-octaethylporphyrin with fluorescein was obtained and identified by means of UV–vis, NMR, IR spectroscopy and ESI-HRMS spectrometry. Using one- and two-dimensional NMR spectroscopy and quantum chemical calculations, it was found that the Sn(IV) cation in the macrocycle is bound to fluorescein through the hydroxo group of the xanthene dye. The spectral, acid-base and fluorescent properties as well as photoresistant to UV-radiation of the synthesized compounds were studied by spectrophotometric method. It was also described possible protolytic and tautomeric processes occurring in the Sn(IV)-2,3,7,8,12,13,17,18-octaethylporphyrin extra-complex with two fluorescein molecules, which has proved to be resistant to degradation into separate fragments in the wide range of medium pH. Given that the synthesized porphyrin-fluorescein triad exhibits a high sensitivity of fluorescence and photostability to the molecule ionization it can be considered as pH-dependent photoactive arrays that simultaneously possess both rotary [due to the Sn(IV) cation] and pH sensing (due to the fluorescein fragments) properties. [ABSTRACT FROM AUTHOR]

Abstract: A new macrocyclic host, which contains a 2,6-bis(oxazol-2-yl)pyridine unit and a 2,7-dialkoxynaphthalene unit tethered by the appropriate length of alkyl side chains is prepared. This host undergoes highly selective complex formation with an adenine nucleobase, accompanied by a fluorescence response in CHCl3 by a combination of multiple hydrogen bonding and π–π stacking interactions. [Copyright &y& Elsevier]

Abstract: The effect of mobile phase pH, column temperature, extraction method and derivatisation time on the fluorescence response and recovery of fumonisin B1 in corn was investigated. Column temperature and mobile phase pH were negatively and positively correlated with the fluorescence response, respectively. Use of an Ultraturrax blender for extraction resulted in higher FB1 recoveries compared to a rotary shaker. In contrast to other reports, maximum fluorescence response occurred after a derivatisation time of 8min. These results reflect on the absolute requirement for standardisation of the aforementioned parameters. [Copyright &y& Elsevier]

We report a Ni-MOF (nickel metal-organic framework), Ni-SIP-BPY , synthesized by using two linkers 5-sulfoisophthalic acid (SIP) and 4,4'-bipyridine (BPY) simultaneously. It displays an orthorhombic crystal system with the Ama 2 space group: a = 31.425 Å, b = 19.524 Å, c = 11.2074 Å, α = 90°, β = 90°, γ = 90°, and two different types of nickel(II) centers. Interestingly, Ni-SIP-BPY exhibits excellent sensitivity (limit of detection, 87 ppb) and selectivity toward the 2,4,6-trinitrophenol (TNP)-like mutagenic environmental toxin in the pool of its other congeners via "turn-off" fluorescence response by the synergism of resonance energy transfer, photoinduced electron transfer, intermolecular charge transfer, π-π interactions, and competitive absorption processes. Experimental studies along with corroborated theoretical experimentation, vide density functional theory studies, shed light on determining the plausible mechanistic pathway in selective TNP detection, which is highly beneficial in the context of homeland security perspective. Along with the sensing of nitroaromatic explosives, the moderately low band gap and the p-type semiconducting behavior of Ni-SIP-BPY make it suitable as a photoanode material for visible-light-driven water splitting. Highly active surface functionalities and sufficient conduction band minima effectively reduce the water and result in a seven times higher photocurrent density under visible-light illumination.

Schematic illustration of the enhanced fluorescence immunoassay via co-coupling with CPBA and Sav-Bio-Protein A for oriented antibody immobilization. [Display omitted] • A homemade polymeric device-based fluorescence immunoassay for Alpha-fetoprotein (AFP) analysis has been developed. • Oriented antibody immobilization was achieved via co-coupling of phenylboronic acid and Protein A. • The antibody bioreactivity and package density on the PMMA substrate are maximumly retained for AFP recognition. • The AFP can be sensitively and specifically detected even from human serum samples. The powerful immunoassay has attracted increasing attention for detecting trace substances. Herein, based on the co-coupling of phenylboronic acid and Protein A for oriented antibodies immobilization, we proposed a polymeric device-based fluorescence immunoassay with enhanced assay performance for Alpha-fetoprotein (AFP) analysis. Unlike traditional physical absorption or chemical covalent conjugation to immobilize antibodies, in this immunoassay, the bioreactivity of AFP antibody was maximumly obtained owing to the oriented immobilization manner. The package density of AFP antibody on the polymethylmethacrylate (PMMA) surface is significantly improved because of the co-coupling case associated distance effect. In addition, the non-specific absorption is greatly inhibited with the combined using of zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) and bovine serum albumin (BSA). These integrated features facilitate the output of strong fluorescence in the presence of AFP but emit very weak background in the absence of AFP. After a typical sandwich immunoreaction, the recorded fluorescence intensity of the immunosensor is proportional to the AFP concentration, showing excellent sensitivity, specificity, and reliability for AFP determination. Comparative studies show the co-coupling is superior than its single coupling counterparts. We envision this unique immunoassay can provide a new avenue for building immunosensors in the fields of disease diagnosis, food safety detection, and environmental monitoring. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOFs was synthesized through one-pot synthesis at room temperature. • Real-time observation of doxorubicin loading/release from MOFs by fluorescence. • Fluorescence intensity enhancement after the pH-triggered doxorubicin release. • The addition of histidine polypeptides increases uptake by HepG-2 cells. Histidine Polypeptide-Hybridized Nanoscale Metal–Organic Framework (fH12/ZIF-8) can be produced effectively in water at room temperature without using any additives. The fluorescein label also provides a useful method to quantify the extent to which the anti-cancer drug doxorubicin (DOX) is loaded into or released from the resulting MOFs. In vitro studies have shown that fH12/ZIF-8 has the useful property of dissolving and controlled rates at low pH. It ruptured fastest in PBS buffer solution with pH 6.3, and the release rate reached 50% at 4 h. Furthermore, it showed that the addition of histidine polypeptides increases uptake by HepG-2 cells. This study integrates drug loading and detecting aspects into a single theranostic platform by a simple and efficient strategy, opening a new route for the construction of advanced drug delivery systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two dumbbell D-π-A-π-D type tetraphenylethene modified cyanostilbene derivative TPEAN had been designed and synthesized. • TPEAN exhibited unique intramolecular charge transfer and aggregation-induced emission characteristics. • TPEAN displayed remarkable piezochromism. The D-π-A-π-D type tetraphenylethene-based cyanostilbene derivative TPEAN had been designed and synthesized. Solvatochromic experiment and theoretical calculation illustrated that TPEAN occurred unique intramolecular charge transfer (ICT) process. Luminogen TPEAN also exhibited AIE activity. The nanoparticles gradually formed and emitted intense fluorescence at high water content in a mixture of THF/water. Interestingly, TPEAN displayed remarkable piezochromism. A emission color change from bright green to dark yellow occurred for the pristine solid of TPEAN after grinding treatment. This emitting color change could recover to its original state after fuming. The current work could be help us to effectively design molecular structure to achieve an obvious fluorescence response to external force. [ABSTRACT FROM AUTHOR]

A novel Dansyl-labeled tetrapeptide sensor (D-P4) was designed for the ultrasensitive detection of mercury ion by spectroscopic analyses. The sensor exhibited an excellent selectivity and sensitivity to Hg2+ with a 'turn-off' fluorescence response. In addition, D-P4-Hg system presented a good 'turn-on' fluorescence response to biothiols. The research findings provide a strategy for the design of new sensors to detect metal ions. • Ultrasensitive Hg2+ and biothiol detection based on the fluorescent peptidyl sensor were developed. • Spectroscopic analyses were applied to study the biointeraction mechanism of Hg2+ to peptidyl sensor. • The possible binding site of Hg2+ to peptidyl sensor was predicted by molecular docking method. • The fluorescent sensor exhibits an excellent selectivity and sensitivity to Hg2+ with a 'turn-off' fluorescence response. Mercury is an environmental contaminant, which is highly toxic even at extremely low concentrations. Long-term accumulation of mercury in human body will damage the central nervous system or digestive tract system. Here, a new fluorescent chemical sensor Dansyl-His-Pro-Gly-Asp-NH 2 (D-P4) was synthesized for the determination of Hg2+. The D-P4 sensor exhibits excellent selectivity and sensitivity to Hg2+ in aqueous solution with a 'turn-off' fluorescence response. Furthermore, D-P4-Hg system displays a good 'turn-on' fluorescence response to biothiols. The calculated binding constant for the 1:1 complex of D-P4 with Hg2 + is 1.07 × 105 M−1, which also confirms the high affinity of D-P4 for Hg2+. Results indicate that the detection limit of D-P4 for Hg2+ is 61.0 nM, and that of D-P4-Hg system for Cys is as low as 80.0 nM. [ABSTRACT FROM AUTHOR]

of molecular species is needed for applications in diagnosis of infections and genetic diseases. Herein, we demonstrate a target DNA-responsive ultrahigh fluorescence signal-on DNA amplification system via periodically programmed building and collapse of DNA networks. In this system, a pair of oligonucleotides of padlock probe (PP) and palindromic hairpin probe (PHP) are utilized. The presence of target DNA firstly hybridizes with PP, allowing the occurrence of rolling circle amplification (RCA) to produce RCA products with tandem repeats in abundance to bind and unfold numbers of PHPs. The conformational change of PHPs enables the building of DNA networks via the intermolecular palindrome pairing, but then makes the DNA networks collapsed via the palindrome-induced strand displacement polymerization. The displaced RCA products are dynamically reused to undergo periodically programmed multiple rounds of DNA network building and collapse. Depend on the bidirectional DNA assembly and disassembly, a strikingly amplified fluorescence can be collected to ultrasensitive and specific detection of target DNA. The practicability has been demonstrated by evaluating target-spiked human serum, saliva, and urine samples with acceptable recoveries and reproducibility. Therefore, this newly explored method opens a promising avenue for the detection of nucleic acids with low abundance in biochemical analysis and diseases diagnosis. Image 1 • A target DNA-responsive amplification system via programmed building and collapse of DNA networks has been built. • The dynamic DNA assembly requires a pair of oligonucleotides of padlock probe (PP) and palindromic hairpin probe (PHP). • The target DNA can be detected depend on the bidirectional manner of DNA assembly and disassembly to amplify fluorescence. • The practicability for analyzing target from human serum, saliva samples has been demonstrated. [ABSTRACT FROM AUTHOR]

A novel supra-molecular compound [Zn(C 4 H 2 N 2 S) 4 ] 2 •(SiF 6)•(BF 4) 2 (1) was synthesized by the reaction of 2-mercapto-1-methylimi-dazole and Zn(NO 3) 2• 6H 2 O. Structural analysis indicates that the compound 1 shows a novel 3D supra hydrogen cluster network structure. The luminescent behavior for the compound 1 has been investigated at room temperature. Results show that compound 1 can be used as a chemical sensor for detecting Fe3+, OH− and five kinds of nitro explosives due to the strong fluorescence property. In particular, the compound 1 exhibits an excellent detection efficiency of 4-nitroaniline (PNN). At last, we researched the mechanism of the quenching effect. A novel supra-molecular compound [Zn(C 4 H 2 N 2 S) 4 ] 2 •(SiF 6)•(BF 4) 2 (1) was synthesized by the reaction of 2-mercapto-1-methylimi-dazole and Zn(NO 3) 2• 6H 2 O. An inorganic-organic hydrogen bond cluster (IOHBC) was formed by six hydrogen bonds which include single and bifurcate hydrogen bonds. Based on the excellent fluorescence property of compound 1, it is found that compound 1 can selectively detect Fe3+ and OH- which the solution concentration is 10-2 M under the interference of other ions. Image, graphical abstract [ABSTRACT FROM AUTHOR]