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Face-centered cubic packing is typically observed for pristine C 60 in the solid state, and one-dimensional alignment structures of pristine C 60 in the solid state are extremely rare. This study presents the synthesis of novel one-dimensional aligned C 60 in single-cocrystal nanosheets, formed from C 60 and N,N,N′,N′-tetraphenylbenzidine (TPB). In C 60 /TPB, which exhibits ambipolar charge transport characteristics, TPB serves as a molecular receptor to facilitate the formation of noncovalent networks wherein C 60 organizes into one-dimensional arrays. The resulting C 60 /TPB nanosheets give rise to a distinct absorption band in the near-infrared region, suggesting the occurrence of charge-transfer interactions between the C 60 and TPB frameworks within the cocrystals. [Display omitted] • One-dimensional aligned C 60 in single-cocrystal nanosheets were synthesized. • The nanosheets were formed from C 60 and N,N,N′,N′-tetraphenylbenzidine (TPB). • C 60 /TPB is ambipolar: TPB forms noncovalent networks and C 60 one-dimensional arrays. • Charge-transfer occurs between the C 60 and TPB frameworks within the cocrystals. • C 60 and TPB contribute to the electron and hole transport properties of C 60 /TPB. [ABSTRACT FROM AUTHOR]

Risk level of benzidine residue to the environment and food safety urges surface enhanced Raman scattering (SERS) substrates to develop with high sensitivity and rapid enrichment. Herein, a hybrid of Au NPs decorated crystalline carbon nitride nano-walls (Au/CCN NWs) is fabricated on Al sheet and employed as a SERS substrate for the first time. An electro-enhanced adsorption strategy is employed to endow as-prepared Au/CCN NWs/Al chip with rapid assay capability. Crystalline phase transition and nano-wall morphology respectively bestows high charge transfer efficiency and favorable enrichment activity upon Au/CCN NWs/Al chip, and the hybrid substrate owns a considerable enhancement factor of 1.76 × 106 under static adsorption mode. Moreover, Au/CCN NWs/Al substrate can achieve the saturation enrichment of benzidine in 120 s with the help of electro-enhanced adsorption, and gains a significantly enhanced signal response compared to static adsorption. Likewise, the highly sensitive response (1 μg L−1), superior reproducibility (RSD = 9.11 %, n = 100) and reliable accuracy (recovery rate of 95.55 %–109.46 %) jointly demonstrate that Au/CCN NWs/Al substrate may be applicable for detecting benzidine residue in actual application. This work offers an integrated solution to both enhance charge transfer efficiency and enrichment activity based on collaborative crystalline phase transition and electro-enhanced adsorption, and may inspire the design of novel noble metal/semiconductor hybrid SERS substrates. [Display omitted] • Crystalline carbon nitride nano-walls (CCN NWs) was constructed via combined molten salt template and hydrothermal assembly. • Electro-enhanced adsorption endowed SERS chip with rapid analysis capability within 120s. • Crystallization transition and nano-wall morphology synergistically improved SERS activity. • Au/CCN NWs/Al chip could rapidly and sensitively detect benzidine in laundry wastewater. [ABSTRACT FROM AUTHOR]

Bi2WO6 with enhanced photocatlytic degradation performance was successfully synthesized by a facile O3 etching method. The photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, and ultraviolet-visible diffuse reflectance spectra. Characterization results revealed that the O3 treated Bi2WO6 photocatalyst has abundant of oxygen vacancies, which could effectively restrain recombination of photon-generated carriers, broaden light absorption region, serve as photocatalytic reaction center. Moreover, the photocatalytic activities of the prepared photocatalysts were evaluated by the photocatalytic degradation of benzidine under a xenon lamp irradiation. The photocatalytic activity of treated Bi2WO6 photocatalyst samples with O3 pose a greater improvement. Among that, the O3-Bi2WO6-3-4 modifying with ozone flux of 3.0 L/min for 4 h photocatalytic degradation of benzidine wastewater reached ~76.0% in 180 min under the irradiation of xenon lamp light (λ = 420 nm), which is about ~2.1 times higher than that of pure Bi2WO6. Moreover, the photocatalytic activities of the modified Bi2WO6 via O3 exhibit without significantly decrease after four cycles, indicating that the photocatalyst has a favourable application prospect. [ABSTRACT FROM AUTHOR]

• A novel compound comprising an acyl-thiourea and amide functional in a single molecular architecture (VII) was successfully prepared in high yield. • SC-XRD, Molecular Docking (MD) study against jack bean urease enzyme, DFT and Hirshfeld analyses were carried out. • Electrostatic interactions, dispersion effects, and total energy components proposes that the primary factor driving crystal stabilization is the electrostatic energy contribution. • The MD studies reveal notable H-bonding, C H π interactions with the active site of urease signifying a potent inhibitor. The new compound 3-methyl- N -((4′-(3-methylbenzamido)-[1,1′-biphenyl]-4-yl)carbamothioyl) benzamide (VII) was prepared with a room temperature procedure. It was synthesized in situ in three steps with an excellent yield of 85 %. The chemical structure of VII was confirmed spectroscopically. Its molecular structure was determined by X-ray structural analysis and then used for a docking study with jack bean urease enzyme. The obtained coordinates were further used for comprehensive DFT and Hirshfeld analyses. Evaluation of the combination of electrostatic interactions, dispersion effects, and total energy components suggests that the primary factor driving crystal stabilization is the electrostatic energy contribution. The molecular docking studies of VII reveal that the combination of acyl-thiourea with an amide functional group (known for their importance in artificial drug design) facilitated a good docking score of -8.7 Kcal/mol. Notable hydrogen bonding and C H π interactions were found. The presence of very efficient hydrogen bonding interactions with the active site of jack bean urease emphasizes that the molecule might serve as a rather potent actual inhibitor for urease enzymes. [Display omitted] [ABSTRACT FROM AUTHOR]

• A 99.9 % probability of carcinogenicity was estimated for 8 benzidine-related-dyes. • A 98.9 % probability of carcinogenicity was forecast for other 251 BZ-related-colorants. • Bayesian forecasting exhibited the potential to enhance predictive toxicology. • Bayesian forecasting showed the potential to increase the impact of nonclinical toxicology. The preclinical identification of health hazards relies on the performance (the historic concordance to the respective gold standard) of regulatorily recommended bioassays. However, any testing with less than 100% sensitivity (or 100% specificity) can deliver false results (outcomes discordant to the respective gold standard). Conversely, the predictive values approach (a.k.a. Bayesian forecasting) weighs (1) the performance of the predictive bioassay (battery, or framework) with (2) the prevalence of -positivity to the respective gold standard- in the most representative category to which the test substance can be allocated. Thus, the predictive values approach (PVA) provides the numeric probability for the toxicity to humans of chemicals that, circumstantially, are evaluable only through nonclinical data. Consequently, the PVA improves the predictivity of nonclinical toxicology, and increases the impact of hazard identifications entirely based on preclinical data. This article aimed to introduce the PVA through a worked example. Due to their toxicological homogeneity and public health relevance, the superfamily of colorants synthesized from benzidine (BZ) or some mutagenic congeners was selected (colorings hereafter mentioned as BZ-related-colorants). Through the PVA, the numeric probability of innate carcinogenicity to humans of 259 BZ-related-colorants was either estimated from rodent carcinogenesis bioassays (RCBs) or predicted from methods alternative to the RCB. A discussion was provided on (1) some limitations and implications of the PVA, and (2) the probable significance of the predictive values figured here for 259 BZ-related-colorings. [ABSTRACT FROM AUTHOR]

• HRP immobilization and degradation of Direct Blue-6 with immobilized HRP were optimized. • Activity of HRP was improved after immobilization on p(HEMA-GMA) cryogel. • More than 94% of Direct Blue 6 degradation was achieved using immobilized HRP. • Toxicity assessment test was realized with D. magna and C. Vulgaris using HRP treated dye solution. • GC–MS data confirmed degradation of Reactive Blue 6 into small molecular weight compounds. Horseradish peroxidase (HRP) was immobilized on the poly(2-hydroxyethyl methacrylate-glycidyl methacrylate) [p(HEMA-GMA)] cryogel and used for the degradation of a benzidine containing azo dye (i.e., Direct Blue-6). The maximum amount of HRP loading was found to be 87.6 mg g−1 cryogel, and the retained immobilized HRP activity was 67% with respect to the same quantity of the free enzyme. Biochemical properties of the HRP preparations were also evaluated along with the stability studied under various denaturizing conditions. The toxicity of the Direct Blue-6 and its degradation products was tested using Daphnia magna. Decrease in the absorbance of the blue color of dye at 590 nm was observed during enzymatic degradation studies. Additionally, Chlorella vulgaris was used as a test organism in the algal growth inhibition studies. After 60 min reaction time, the Direct Blue-6 dye and its degradation product were enzymatically removed from the medium. Thus, after treatment with HRP approximately 60-min, the medium was non-toxic for both D. magna and C. vulgaris. The Direct Blue-6 dye and its degradation product toxicities were reduced after enzymatic treatment from 99.6 to 7.3%. It should be noted that the initial degradation products appeared to be extra toxic compared to the pristine dye. [ABSTRACT FROM AUTHOR]

• A novel Schiff base compound named: N, N'bis (1,2-biphenyl ethanone) benzidine (BB) has been synthesized by the reaction of benzidine and benzyl under reflux condition. • The structure of compound was confirmed by FTI, UV-vi's spectroscopies and single-crystal X-ray diffraction technique. • The graphical tools based on Hirshfeld surfaces and two-dimensional (2D) fingerprint plots have proven useful to visualize and analyze intermolecular interactions in polymorphs of molecular crystals. • The electrochemical properties of the studied Schiff base have been investigated by cyclic voltammetry. A novel Schiff base compound named: N,N'bis(1,2-biphenylethanone) benzidine (BB) has been synthesized by the reaction of benzidine and benzyl under reflux conditions. The structure of the obtained compound was confirmed by FT-IR spectrum, UV–vis, 1H NMR, 13C NMR spectroscopies and by the single-crystal X-ray diffraction technique. The compound crystallized in the monoclinic system, space group C2/c with the following unit cell parameters a = 13.4126(8)(Å) , b = 10.6584(7)(Å), c = 21.1768(12)(Å) and β =103.549(4)°, and Z = 8, V = 2943.1(3) (Å3), T = 293(2) K. The final R 1 was 0.0317 (I >2σ(I)) and wR 2 was 0.100 (all data). Then, we present a detailed analysis of the structure of N,N'bis(1, 2-biphenylethanone) benzidineby using Hirshfeld topology analysis. The graphical tools based on Hirshfeld surfaces and two-dimensional (2D) fingerprint plots have proven useful for visualize and analyze intermolecular interactions in polymorphs of molecular crystals. The electrochemical properties of the studied Schiff base have been investigated by cyclic voltammetry in dimethylformamide containing tetraethylammonium perchlorate as a supporting electrolyte at a scan rate of 100 mV.s–1. The obtained redox potentials of the compound (BB) confirm also the formation of the azomethine group. [Display omitted] [ABSTRACT FROM AUTHOR]

The surface chemical composition of materials is essential for regulating their charge trapping and storage capabilities, which directly affect their electret performance. Although chemical modification of materials to alter electret performance has been investigated, the mechanism through which electret properties are regulated more systematically via chemical customization has not been elucidated in detail. Herein, p -phenylenediamine, benzidine and 4,4′-diaminotriphenyl, which have different conjugated strength functional groups, were selected to chemically tailor the surface of bamboo pulp fibers to regulate the electret properties and elucidate the regulatory mechanism more systematically. The results showed that the charge trapping and storage properties of materials could be regulated by introducing functional groups with different conjugated strengths to their surfaces, realizing the regulation of the electret properties. Moreover, the charge trapping and storage ability could be tailored more specifically by regulating the number of functional groups. By chemical customization to provide electrostatic effects to the materials, the purification time was reduced by approximately 45 %–52 %. More importantly, a relatively systematic mechanism was proposed to elucidate the effect of the conjugate group strength on the charge trapping and charge storage properties of the material. These findings will provide guidance for the investigation of chemical modifications to regulate the electret performance of materials. [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesis of a new compound (N, N-Bis (2,4-dihydroxy benzaldehyde) benzidine) • Chemical and theoretical characterization was carried to approve the synthesized new compound. • Quantum chemical characterization (DFT) was used to find some physical parameters related to the anti-corrosion properties of our compounds. In this work, a new compound, N, N-Bis (2,4-dihydroxy benzaldehyde) benzidine (III), was synthesized by utilizing acetic acid-mediated condensation of two reactants, benzidine (I) and 2,4 dihydroxybenzaldehyde (II). The synthesis method involved combining two reactants (I) and (II) in an acetic acid solution which formed a new compound that was isolated, purified, and confirmed. The structure of the molecule (III) was experimentally characterized using FT-IR (Fourier Transform Infrared Spectroscopy), as well as 1H and 13C NMR (Nuclear Magnetic Resonance) spectroscopy. To further investigate the structure (III), Density Functional Theory (B3LYP/cc-pVDZ) was used to theoretically calculate the ideal molecular structure, its vibrational frequencies, and the chemical shifts of its 1H and 13C NMR spectroscopic signals. The agreement between the theoretical and experimental spectroscopic results confirmed the validity of the synthesized molecule's structure. Furthermore, the dipole moment (µ), hardness (ɳ), softness (σ), electronegativity (χ), electrophilicity index (ω), nucleophilicity index (ε), and chemical potential (Pi) of the compound were examined to explore their correlation with corrosion inhibition efficiency. By analyzing the transferred electrons, it was possible to gain insight into the reaction between the iron surface and organic molecules. The results suggested that the corrosion inhibitors had a positive affiliation with the quantum chemical parameters processes, which indicated that it was possible to predict the performance of the corrosion inhibitors without having committed to any actual tests or experiments. [ABSTRACT FROM AUTHOR]

Abstract N 4 , N 4 ′ -dibutyl-3,3′-diaminobenzidine target molecules were fashioned and characterized using analytical (UV, NMR, FT-IR, Mass, and CHNS analysis) methods. Optimized molecular geometry, NMR chemical shift value and vibrational frequencies of the N 4 , N 4 ′ -dibutyl-3,3′-diaminobenzidine in the pulverized state were computed using the density functional theory (DFT) B3LYP method with 6-31G(d,p) basis set. The optimized values interpreted and were related to empirical values related literature. In addition to DFT calculations, natural bond orbital investigation (NBO), HOMO and LUMO and NLO possessions were computed at the same level of theory. A synthesized target molecule about 95% yield was achieved using 3, 3′-dinitro-[1, 1′-biphenyl]-4, 4′-diamine as the starting material. Spectroscopic techniques were confirmed the chemical formula of the synthesized compound as C 20 H 30 N 4. Thus was confirmed also by CHNS analysis. Furthermore, molecular docking was carried out for a study of molecular physicochemical, ADME. The molecular physicochemical analysis revealed 2 violations and ADME analysis exhibited high gastro-intestinal (GI) effect. Docking studies showed the ability of N 4 , N 4 ′ -dibutyl-3,3′-diaminobenzidine to dock with all the 7 enzymes/proteins using the patch dock method. Graphical abstract Image 1 Highlights • First time we have synthesized N 4 , N 4 ′ -dibutyl-3,3′-diaminobenzidine monomer and its confirmation were investigated using various analytical techniques. • The vibrational frequencies and electronic absorption wavelengths were calculated by density functional theory and compared with their corresponding experimental results. The theoretical results are in good agreement with the experimental values. • The target molecule N 4 , N 4 ′ -dibutyl-3,3′-diaminobenzidine physiochemical and molecular docking analysis of 7 proteins/enzymes were performed and discussed its docking and binding efficiency. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Poly-TPD is selected to dilute P3HT as active layer for OFET by solution process. • OFET-based NO 2 gas sensor can be operated at room temperature. • Responsivity is gradually improved with the increasing degree of dilution. • Limit of detection as low as 242.6 ppb is realized. Abstract Solution-processed organic field-effect transistor (OFET) has great potential in detecting various hazardous gases including nitrogen dioxide (NO 2). To overcome the bottleneck of weak gas adsorption/interaction capability in single-semiconductor sensing layer, semiconductor composites are used to enhance the sensing response. Here, we report an OFET-based NO 2 sensor whose active layer consists of diluted poly(3-hexylthiophene-2,5-diyl) (P3HT) with poly[ N , N' -bis(4-butylphenyl)- N , N' -bis(phenyl)benzidine] (poly-TPD). Due to the site-increase effect induced by phase segregation, the 90% diluted device possesses a more than 3-fold enhancement of current responsivity. Furthermore, when the gate voltage is switched from −40 V to 0 V, this device embodies 4.6-fold and 43.6-fold improvements at 0.3 ppm and 30 ppm, respectively. Meanwhile, decent selectivity, environmental stability and an excellent limit of detection of 242.6 ppb are realized. [ABSTRACT FROM AUTHOR]

Abstract C.I.Pigment Yellow 155 (Y 155) is an important bisacetoacetarylide disazo yellow pigment with a unique structure, which has the potential to be an alternative for benzidine yellow pigments due to its superior solvent resistance and light fastness. It is essential to investigate the crystal structure of Y 155 to understand the relationship between the structure and technical performance. Y 155 crystallizes in the triclinic P 1 (—) space group. The molecule exists in the bisketohydrazone form which is consistent with that of disazoacetoacetanilide pigments (Diarylide Yellows). Different from the unsubstituted analogue (BADA), Y 155 molecules are approximately planar due to stronger intramolecular hydrogen bonding. In Y 155 crystals, each molecule is interleaved in two adjacent layers above and below. The color and the technical performance are discussed in relation to its crystal structure especially involving in the role of four methyl formate groups. Graphical abstract The crystal and molecular structure of C.I.Pigment Yellow 155 is disclosed and the technical performance in relation to crystal structure is discussed. Image Highlights • The crystal and molecular structure of C.I.Pigment Yellow 155 is disclosed. • Different from the unsubstituted analogue (BADA), Y155 molecules are approximately planar.. • The technical performance in relation to crystal structure is discussed. [ABSTRACT FROM AUTHOR]

Abstract Capacitive deionization (CDI) is a promising technology for water 0. The electrode material plays a vital role in electrosorption capacity. Its porous nanostructure can promote capacitive deionization performance. Here, a “one-pot” synthesis of p -phenylenediamine- or benzidine- (DAB) functionalized graphene (DAB-mGO) was achieved using graphene oxide (GO) as a precursor by simultaneous nucleophilic addition, an amide reaction and an electrostatic self-assembly technique. DAB-mGO exhibits a significantly increased conductivity, specific surface area and pore volume compared with GO, which indicates that it can be used as a CDI electrode material for desalination in brackish water. DAB-mGO 130 that was obtained at 130 °C exhibited electrosorption capacities of 7.88, 8.02 and 13.55 mg/g in Na+, Mg2+, Ca2+ solutions, respectively, at 1.4 V. These values are ~1.3–1.5 times higher than commercial activated carbon. These observations indicate that the simple organic functionalization of GO is an effective approach to increase the CDI performance because of the generation of useful porous nanostructures. A rational combination of organic molecules and inorganic GO can be used to fabricate environmental and economical CDI electrode for application in CDI and energy storage. Graphical abstract Unlabelled Image Highlights • Highly pore-expanded benzidine-functionalized graphene framework was fabricated. • The porous nanostructure can promote capacitive deionization performance greatly. • Organic functionalization of GO can increase the CDI performance efficiently. • DAB-mGO may be a promising candidate as an electrode material for CDI technology. [ABSTRACT FROM AUTHOR]

Innovative benzidine-free PANI-based inks for electrically conductive inkjet printed devices were developed and tested and the results compared with those obtained by traditional PANI. NMR investigations evidenced the presence of quinones and phenolic groups on the backbone of the innovative PANIs that are thought being responsible for the higher solubility in DMSO. A mechanism of reaction was proposed. The numerous characterizations (NMR, UV–Vis, FTIR, XPS and electrical investigations) allowed to compare protonation level, doping level, valence band maximum for both the type of PANI. The correlation among structural properties, printability, conductivity and solubility was discussed. [ABSTRACT FROM AUTHOR]

Graphical abstract A colorimetric probe based on redox reaction of 3,3ʹ,5,5ʹ-tetramethylbenzidine with HAuCl 4 , has been designed for the determination of uric acid. Abstract A simple and economical colorimetric probe for the detection of uric acid (UA) based on redox reaction of 3,3ʹ,5,5ʹ-tetramethylbenzidine (TMB) with HAuCl 4 was designed. A novel chromogenic reaction was primarily demonstrated based on the reaction between HAuCl 4 and TMB, which produces many color responses from red to blue in the resulting solutions. In this method, the colorless TMB can be oxidized by HAuCl 4 to generate oxidized TMB (oxTMB) and induce a blue color solution which corresponding to the absorption peak at 652 nm. However, HAuCl 4 would be reduced in the presence of UA, which inducing a blue color diminishing of HAuCl 4 -TMB system and decrease of the absorbance at 652 nm because the content of HAuCl 4 was declined in the solution. Based on this phenomenon, we proposed a method to detect UA which does not require nanomaterials or organic probes. The detection conditions, pH value, incubation time and the concentration of HAuCl 4 and TMB were optimized. The probe displayed a linear response in the range of 0.001–8.0 μM and 8.0–80.0 μM, with a detection limit of 0.67 nM (S/N = 3). This method has been successfully applied to the determination of uric acid in human urine samples. [ABSTRACT FROM AUTHOR]

A rapid and facile approach was developed for the synthesis of core-shell structured magnetic covalent organic framework nanobeads by using the monodisperse Fe 3 O 4 nanoparticles (NPs) as magnetic core, and 1,3,5-triformylbenzene (Tb) and benzidine (Bd) as two building blocks (denoted as Fe 3 O 4 @TbBd), which were explored as an adsorbent for magnetic solid-phase extraction (MSPE) of estrogens from human urine sample. The core-shell structured Fe 3 O 4 @TbBd nanobeads showed some attractive features involving high specific surface area (202.18 m 2 /g), uniform pore size distribution (2.8 nm), high magnetic responsivity (41.4 emu/g), as well as excellent thermal and chemical stability, which made it an ideal adsorbent for selective isolation and enrichment of estrogens. Some parameters influencing extraction efficiency, including adsorbent dosage, extraction time, pH, ion strength, desorption solvent and desorption time were investigated systematically. Combined with HPLC–MS, a simple, fast, and sensitive method was developed for the enrichment and sensitive determination of seven estrogens, which showed good linearity (r > 0.9978) in the range of 0.005–10 μg/L, low limits of detection (0.2–7.7 ng/L, S/N = 3), low limits of quantification (0.6–25.6 ng/L, S/N = 10), high enrichment factors (75–197 fold), and good precision with relative standard deviations (RSD) lower than 4.8% for intra-day and 6.7% for inter-day. The proposed method was successfully applied to the analysis of trace estrogens in urine sample of pregnant woman with good recoveries (80.6–111.6%), demonstrating the promising potential of the Fe 3 O 4 @TbBd nanobeads as adsorbent in sample pretreatment. [ABSTRACT FROM AUTHOR]

Three-dimensional printing (3DP) technologies provide great opportunities for prototyping devices with designed geometric functionality. As a further example of a multifunctional device manufactured using 3DP technologies, this paper describes a multi-well plate—fabricated using a fused deposition modeling-type 3D printer and then treated with a post-printing coating of peroxidase-mimicking platinum nanoparticles (PtNPs)—that (i) catalyzes the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H 2 O 2 ), (ii) allows determination of substances that can be oxidized by their specific oxidases to produce H 2 O 2 , and (iii) facilitates measurement of the absorbance of samples after direct loading into a plate reader. After method optimization, the analytical applicability of the PtNP-coated 3D-printed multi-well plate was illustrated in terms of reusability and stability, reaction kinetics, analytical performance, and the respective determination of glucose and lactate concentrations in urine, plasma, serum, and brain microdialysate samples. Such post-printing functionalization schemes should promote 3DP technologies for the future fabrication of multifunctional devices and an expansion of their practical applications. [ABSTRACT FROM AUTHOR]

Herein, a novel benzidine based fluorescent chemosensor was developed to detect two important heavy metal ions viz. Sn 2+ and Pb 2+ in microheterogenous medium (DMSO-water,1:9 v/v). Benzidine based fluorescent coordination compound (BCc) was found to be an excellent receptor for the aforementioned ions via significant fluorescent enhancement which may be attributed to the inhibition of charge transfer process and an efficient chelation enhanced fluorescence (CHEF) effect. A good linear relationship between fluorescence intensity and concentrations of Sn 2+ and Pb 2+ ions was obtained in the range of 0–120 µM with the detection limit of 0.37 µM and 0.32 µM respectively. Interestingly, no interference was observed for 18 other tested metal ions making it highly selective probe for the detection of Sn 2+ and Pb 2+ ions. The multiplexed sensing ability coupled with prompt metal ion recognizing power, make this sensor specifically attractive for environmental toxicology and biomedical applications. [ABSTRACT FROM AUTHOR]

Organic light-emitting devices (OLEDs) with a poly( N , N ′-bis-4-butylphenyl- N , N ′-bisphenyl)benzidine (poly-TPD):octadecylamine (ODA)-graphene quantum dots (GQDs) hole transport layer (HTL) were fabricated to enhance their efficiency. Photoluminescence (PL) and PL excitation spectra showed that the optical energy bandgap of the ODA-GQDs was 2.7 eV, and ultraviolet photoelectron spectroscopy spectra demonstrated that the edge of the highest occupied molecular orbital of the ODA-GQDs was 5.3 eV below the Fermi level. While the operating voltage of the OLEDs with a PVK:ODA-GQD (9.77 V, 0.25 wt%) HTL at 10 mA/cm 2 was 0.8 V lower than that of the OLEDs with a poly-TPD HTL (10.57 V), their current efficiency was larger by more than 20% than that of the OLEDs with poly-TPD (32.88 cd/A) due to an increase in the number of holes injected from the ITO to the HTL. The number of injected holes was increased due to a reduction of the energy barrier and an increase in the conductivity. [ABSTRACT FROM AUTHOR]

The peroxidase-like activity of 2',7'-difluorofluorescein (DFF), was investigated using 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogenic substrate in the presence of H 2 O 2 . DFF could catalyze oxidization of TMB by H 2 O 2 to produce a blue colored oxidation product. Effect of various reaction conditions, such as pH, temperature, H 2 O 2 concentration and reaction time on the catalytic activity of DFF was studied. The peroxidase-like activity of DFF was found to follow Michaelis–Menten kinetics, and its catalysis accorded with ping-pong mechanism. The calculated kinetic parameters (K cat ) of DFF catalysis showed higher peroxidase-like activity than fluorescein and 2′,7′-dichlorofluorescein (DCF). According to the radical capture and electron spin resonance (ESR) spectroscopy results, we confirmed that hydroxyl radical (•OH) is the active specie of catalytic process. It is known that the oxidation of galactose by galactose oxidase (GAOx) enzyme leads to the formation of H 2 O 2 , the H 2 O 2 released in this reaction was consequently quantified using DFF as peroxides mimics and TMB as the chromogen. Thus, a combination of above two reactions was exploited to establish a method for galactose detection. Under the optimum conditions, the linear range of this method was from 10 μM to 20 mM with the detection limit down to 3 μM. Moreover, the developed method was applied to detect galactose in urine samples. Our work will facilitate the utilization of DFF intrinsic peroxidase-like activity in medical diagnostics and biotechnology. [ABSTRACT FROM AUTHOR]

Lawsone redox (LQ) mediator was covalently bound to granular activated carbon (GAC) by Fischer esterification. A high LQ adsorption capacity on GAC was achieved (∼230 mg/g), and desorption studies showed strong chemical stability. Furthermore, kinetic experiments with solid-phase redox mediator (RM) and their controls (soluble RM, GAC and anaerobic sludge) were tested for decolorization of congo red dye at initial concentration of 175 mg/L. Benzidine, a by-product of complete congo red reduction, was also measured by HPLC analysis along the kinetic experiments. The highest percentage of decolorization after 24 h of incubation was achieved in cultures with soluble (77%) and immobilized (70%) LQ. In contrast, low decolorization efficiency was reached in anaerobic bio-reduction assays with unmodified GAC (47%) and anaerobic sludge (28%) after 24 h. Removal of congo red by adsorption onto LQ-GAC was negligible. The rate of benzidine production was slower than decolorization rate, suggesting that one azo bond of congo red is selectively broke and followed by a slower breaking of the second azo bond, consequently, appearance of benzidine in solution. These issues could be attributed to the steric rearrangement and the inhibitory effects of the produced aromatic amines in the biotransformation process. [ABSTRACT FROM AUTHOR]

In this work, cobalt oxyhydroxide nanoflakes (CoOOH nanoflakes) were reported to possess a high oxidizability toward TMB for the first time and based on which we have developed a new strategy for qualitative and quantitative detection of ascorbic acid (AA). In our design, CoOOH nanoflakes can directly oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) to oxTMB with an obvious blue color emerging, and AA can selectively inhibit the oxidation of TMB to oxTMB by resolving CoOOH nanoflakes to Co 2+ , resulting in a decrease in the absorbance of oxTMB and bleaching of blue color. As such, the concentration of AA could be identified very easily by UV–vis spectroscopy and bare eyes. Under optimal conditions, this sensing platform showed a highly sensitive response to AA with a detection limit of 142 nM and a short assay time of 5 min. This assay was also successfully used to quantify AA in human serum samples and practical food samples. Importantly, using this fabricated sensing strategy, we have further developed a paper-based strip sensor for AA detection with satisfactory results, showing its great potential for point of care applications. [ABSTRACT FROM AUTHOR]

In this study, we have developed bridge heterologous ELISA for the detection of 17α- Methyltestosterone by incorporating aromatic spacers between 17α-Methyltestosterone-3-Carboxymethyloxime and Horseradish peroxidase label through N-hydroxysuccinimide mediated carbodiimide reaction method. The immunogen 17α-Methyltestosterone-3-Carboxymethyloxime-Bovine serum albumin used to generate the antibody was also prepared by the N-hydroxysuccinimide mediated carbodiimide reaction without using any spacer. We have studied the impact of bridge/aromatic spacers on functional parameters i.e. sensitivity, affinity and ED 50 of the bridge heterologous assay and compared it with homologous assay. The five combinations of bridge heterologous assay using 17α-Methyl testosterone-3-CMO-BSA antiserum and 17α-MT-3-CMO-4,4'-Diaminodiphenyl sulphide-HRP, 17α MT-3-CMO-4,4'-Oxydianiline-HRP, 17α-MT-3-CMO-Benzidine-HRP, 17α- MT-3-CMO-p-Phenylenediamine-HRP and 17α-MT-3-CMO-Dapson-HRP enzyme conjugates were evaluated. Out of these five combinations, the combination 17α-MT-3-CMO-BSA with 17α-MT-3-CMO-Benzidine-HRP showed the best results. Sensitivity, affinity and ED 50 were improved and found to be 0.02 ng/mL, 0.086 × 10−8 L/mol and 2.95 ng/mL than homologous assay where Sensitivity, affinity and ED 50 were 0.11 ng/mL, 0.02 × 10−8 L/mol and 5.78 ng/mL respectively. The cross-reactivity for this bridge heterologous assay combination was seen with only 4 steroids (6-hydrotestosterone- 6%, Testosterone-5.14%, Danazol-0.9% and Nandrolone-0.85%) instead of eight steroids (6-hydrotestosterone-43.75%, Testosterone-38.3%, Danazol-25.14%, Androstenediol-19.16%, Nandrolone-19%, Metandienone-5%, Androstenedione-3.52%, and 17α dimethyltestosterone-2%) as in homologous assay out of 59 structurally related steroids. Thus, the results of this study conclude that the incorporation of aromatic spacer (bridge) in enzyme conjugate has a crucial role in improving sensitivity, specificity, ED 50 and affinity of the developed assay. The assay was then studied for parameters such as recovery (97.4%–108.6%), precision (Inter and Intra-assay coefficient of variation <10%), correlation coefficient (R2 = 0.96) by comparing with the commercial kit and validated by measuring levels of 17α- methyltestosterone in rat serum after administering them. [Display omitted] • In this study, Five aromatic spacers; p-Phenylenediamine (PPD), 4,4'-Oxydianiline (ODA), 4,4'-Diaminodiphenyl sulphide (DPS), Benzidine (B), Dapson (D) for the first time have been used in the development of 17 alpha methyl testosterone ELISA. • Out of five combinations, the combination of antiserum 17α MT-3-CMO-BSA with enzyme conjugate 17α MT-3-CMO-Benzidine-HRP showed the best results. • This assay was studied further for analytical variables like Recovery, and Precision (Inter and Intra-assay coefficient of variation). • Correlation (R2 = 0.96) and validation of the assay was done by comparing with commercially available kit. • The study concludes that incorporation of aromatic spacer (bridge) in enzyme conjugate have fundamental role in improving sensitivity, specificity, ED 50 and affinity of the developed assay. [ABSTRACT FROM AUTHOR]

Recently, inorganic nanoparticles have been studied as hole transporting materials (HTM) in perovskite solar cells (PSCs). Inorganic HTMs are believed to provide better stability compared to conventional organic HTMs, such as spiro-OMeTAD. One of the challenges of nanoparticle HTMs is the high density of defects at the interface with the perovskite film, which reduces the device's fill factor. In this study, we use N, N′–di (naphthalene-1-yl)-N, N′ diphenyl benzidine (NPB) small molecules to passivate the surface of perovskite films in carbon-based PSCs with CuInS 2 nanoparticles as the HTM. By applying NPB, trap density decreases from 1.35 × 1016 cm−3 to 5.09 × 1015 cm−3. NPB interface passivation results in a power conversion efficiency (PCE) of 16.11% compared to the control device with PCE of 14.92% in carbon-based perovskite solar cells. Moreover, improved contact angle was obtained for NPB surface-treated film (61.9°) compared to the reference film (40.6°), providing better protection against moisture induced degradation. The surface-treated devices maintained 92% of their efficiency after 4000 h of storage at ambient condition, while the control device showed a rapid and notable degradation, losing >58% of the initial efficiency under the same condition. [Display omitted] • NPB is applied as a passivation layer of perovskite/nanoparticle CuIn 2 S interface. • The CuIn 2 S/Carbon hole-collectors are applied for mixed cation/halide PSCs. • NPB acts as a lewis base to passivate the perovskite surface defects. • NPB-treated samples maintain 92% of their PCE after 4000 h in ambient conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • CDs were facilely derived from amoxicillin and sodium carbonate. • CDs own strong fluorescence characteristics, stability and water solubility. • CDs exhibit good fluorescent stability in weak acid and high salt environments. • CDs show high sensitivity and selectivity for benzidine based on static quenching. Amoxicillin is one of the most important semi-synthetic penicillin broad-spectrum β-lactam antibiotics and has achieved many applications. There are few reports on its application for synthesizing carbon dots (CDs). Present work explored the possibility of amoxicillin converted into CDs with sodium carbonate used as the co-reactant employing facile hydrothermal method. The obtained CDs exhibited good selectivity and sensitivity to benzidine and could be explored as an effective fluorescence probe for monitoring benzidine. The fluorescence intensity of CDs was quenched based on the principle of static quenching due to the formation of a non-fluorescent complex between CD and benzidine. Within the range of 0.2–2 μM and 2–16 μM, CDs possessed good linear characteristics, high sensitivity, and a low detection limit of 0.08 μM. The results demonstrated that the fluorescence probe possessed the merits of simplicity, rapidity, low cost, short analytical time, high selectivity and sensitivity, and good stability. According to the verification results from the real water samples, the fluorescence probe had high reliability and feasibility, and could be employed for monitoring benzidine in waters. [ABSTRACT FROM AUTHOR]

Therapeutic monoclonal antibodies (mAbs) have been successfully applied to treat various diseases and shown a promising prospect in medical treatment. MAbs have some unique characteristics when compared with small chemical drugs, and their pharmacokinetic (PK) properties are much more complex than those of small chemical drugs, whose eliminations are usually linear. In this study, a new model was established through taking into account the mechanisms of the elimination of mAbs. The proposed model was applied to the modeling and simulation of two kinds of mAbs, including bevacizumab and etanercept, in PK studies of healthy volunteers and eligible patients, and the classical linear compartment model was set as control. The goodness-of-fit of the fitting concentration-time curve of mAbs was calculated to verify the accuracy of both models during the modeling and simulation. The accuracy of the proposed model was better than that of classical linear compartment model in healthy volunteers and even much better in patients. The proposed model demonstrates a stronger ability in the modeling and simulation of mAbs, and may provide a new option for the PK studies of those reagents. [ABSTRACT FROM AUTHOR]

A novel ultrasound-assisted liquid phase microextraction (UALPME) based on environmental friendly extractants, deep eutectic solvent (DES) was first time presented for speciation of selenium. In present study, five DES solvents of different composition was prepared and used as efficient extractive medium for hydrophobic chelate of Se(IV) with 3,3′-Diaminobenzidine (DAB). The total inorganic Se species were determined after pre-reduction of Se(VI) to Se(IV), prior to applying developed method. The concentration of Se(VI) was calculated by the difference of Se(IV) values and total selenium contents. The concentration of Se in DES rich phase was measured with electrothermal atomic absorption spectrometer (ETAAS). The effects of different parameters on extraction efficiency of study analyte, including pH, ligand concentration, type and volume of DES, sonication time, volumes tetrahydrofuran and aqueous samples were examined. At the optimum conditions, limit of detection and quantification, preconcentration factor, and relative standard deviation (RSD %) were determined as 4.61 ng L −1 , 15.4 ng L −1 , 50% and 4.1%, respectively. The accuracy of the presented method was confirmed by analysis of certified reference material and standard addition method for different water and ice tea samples. The developed method was effectively applied to real water and food samples. [ABSTRACT FROM AUTHOR]

A dynamic three-dimension (3D) metal-organic framework, namely JUC-199 [Zn 4 (TBCB)(H 2 O) 6 ]·5DMAc, was designed and synthesized under the solvothermal condition. The resultant crystal was successfully constructed by an organic ligand 2,2′,6,6′-Tetrakis[3,5-bis-3,5-benzenedicarboxylate] benzidine (H 8 TBCB) and [Zn 2 (COO) 4 ] inorganic clusters. Interesting, the single crystal X-ray diffraction illustrated that JUC-199 could entirely transform into JUC-199a only in ethylene glycol monomethylether (EGME) after two days, which possessed obviously different lattice parameters. In addition, JUC-199a exhibits an obviously yellow fluorescence, whereas JUC-199 doesn't show any fluorescence property. Furthermore, the obtained samples were characterized in detail. [ABSTRACT FROM AUTHOR]

We studied in this work the properties of a new membrane (TR-PBO) obtained by solid state thermal rearrangement at 450 °C of a recently developed polyimide precursor, (mHAB-6FDA), which was synthesized by reaction of (3,3-diamino-4,4-dihydroxybiphenyl, mHAB) with 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA). The mHAB monomer is an isomer of the commercial 3,3′-dihydroxybenzidine (pHAB), used to form the more popular polyimide precursor pHAB-6FDA. TR-PBO membranes obtained from mHAB-6FDA showed excellent CO 2 permeability (720 Barrer) and good CO 2 /CH 4 ideal selectivity of 23. We found out that the thermal rearrangement enhances the solubility and diffusion coefficients of CO 2 at 10 bar by factors as high as 1.3 and 5, respectively. Larger enhancements, however, were observed in the case of CH 4 , causing the diffusivity selectivity to decrease by a factor of 2.6 and the solubility selectivity to decrease by a factor of ~1.5 upon rearrangement. The pure gas solubility was modeled with the Dual Sorption Mode model and the NELF model. The two models were then used to predict the mixed gas behavior in terms of solubility-selectivity, highlighting the effects of competition that are consistent with those observed in other glassy polymers. We also performed moisture sorption tests and gas permeability measurements in the presence of humidity. It was observed that the thermal rearrangement increases the membrane hydrophobicity and, consistently, the CO 2 and CH 4 permeability of mTR-PBO membranes is much more stable in the presence of humidity than that of the precursor polyimide membranes. Finally, the effect of aging on the membrane performance was analyzed. A 30% decrease in the CO 2 permeability of TR polymer membranes (around 50 µm thick) was observed after 6 months, while the selectivity increased by 20%. These results indicate that, even after 6 months, the performance of the TR polymer membrane was outstanding and close to Robeson's upper bound. [ABSTRACT FROM AUTHOR]

In this article, we demonstrated a facile method to prepare the porphyrin [5,10,15,20-Tetrakis (4-carboxyl phenyl)porphyrin] functionalized ZnS nanoparticles (H 2 TCPP-ZnS nanocomposites) under the mild conditions. Porphyrin molecules serves as both a functional molecule and stabilizer. TEM images showed that H 2 TCPP-ZnS nanocomposites are composed of nanoparticles with ca. 5–8 nm in size. The nanocomposites were for the first time developed as a peroxidase mimetic with catalytic activities and could catalyze the colorimetric reaction of H 2 O 2 and 3,3′,5,5′-tetramethylbenzidine (TMB), where the oxidized TMB showed a typical absorption peak at 652 nm. Kinetic analysis indicated that the catalytic behavior was in accordance with typical Michaelis–Menten kinetics. Moreover, H 2 TCPP-ZnS nanocomposites could accelerate H 2 O 2 to decompose into ·OH radicals. The intrinsic peroxidase-like activity of H 2 TCPP-ZnS nanocomposites is due to the synergistic effect of H 2 TCPP as well as ZnS in the nanocomposites. Based on these findings, a simple and sensitive colorimetric assay to detect H 2 O 2 and glucose with a range of concentration from 0.01 to 0.06 mM and from 0.005 to 0.5 mM, respectively. In addition, this nanosensor can also be used for glucose detection in diluted serum. [ABSTRACT FROM AUTHOR]

Due to the harmful nature of 4,4′-diaminobiphenyl (DABP) to the environment and human health, the determination of DABP is of great significance and has received great attention. However, there is no electrochemical method reported to detect DABP. In this paper, perylenetetracarboxylic acid (PTCA) noncovalently functionalizes carbon nanohorns (PTCA-CNHs) nanohybrids were produced using a simple method and applied for the first electrochemical sensing of DABP. Herein, PTCA has two key advantages for functionalizing CNHs in DABP analysis: (I) PTCA could improve the dispersibility of CNHs in water and (II) enhance the accumulation capacity of DABP on PTCA-CNHs surface by means of the electrostatic interactions between PTCA (negative) and DABP (positive). The results show that the oxidation current of DABP at the PTCA-CNHs modified screen printed carbon electrode (SPCE) is much higher than that of the CNHs/SPCE and bare SPCE. The PTCA-CNHs/SPCE has a linear response range of 5.0 to 400.0 nM with a detection limit of 1.8 nM towards DABP detection. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing technologies enable rapid laboratory-scale customization of experimental devices to fit the user’s requirements. To demonstrate how 3D-printed objects can be functionalized through incorporation of reactive substances into the raw materials prior to printing, this paper describes a multi-well plate fabricated using polylactic acid (PLA) filaments that had been treated in advance with iron oxide (Fe 2 O 3 , Fe 3 O 4 ) nanoparticles that possess intrinsic peroxidase activities. The fabricated multi-well plate efficiently catalyzed the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by the peroxidase substrate hydrogen peroxide and allowed measurements of the resulting absorbance through direct loading of the plate into a plate reader. The applicability of this 3D-printed peroxidase mimic–incorporating multi-well plate has been examined in terms of the device’s reusability and analytical performance, analyses of reaction kinetics, and the high-throughput determination of glucose concentrations in clinical and food samples. The results suggest that this functionalization scheme can diversify the utility of current 3D printing technologies in the fabrication of experimental devices with properties comparable with or superior to those of conventional systems. [ABSTRACT FROM AUTHOR]

Plaque assays of human respiratory syncytial virus (HRSV) are time-consuming, requiring 4 to 7 days for plaque formation and several hours for dye staining. Here, we describe a simple method by which RSV plaques can be visualized and counted with the naked eye only 2 days after infection of HEp-2 cells. In this assay, the infected cells are stained with monoclonal antibodies and the plaques are developed using diaminobenzidine (DAB). We tested the accuracy of this new plaque assay by comparing the results obtained on days 1, 2, 3, 4, 5, and 6 post-infection. The whole procedure is significantly simpler than the traditional method, with an immunostaining process of around 1.5 h. Our method is rapid, accurate, and simple; thus, it has the potential to significantly contribute to studies related to RSV disease. [ABSTRACT FROM AUTHOR]

The visible-light-promoted photodegradation of two carcinogenic primary azo-dye metabolites (BZ-C), represented by the colourless water-contaminants Benzidine (BZ) and o -Tolidine (OT), was studied in water-methanol solution. It was done in the presence of air and the natural pigment riboflavin (Rf) as a photosensitizer. These conditions reasonably mimic a natural environment scenery. Both BZ-C interact with the reactive oxygen species (ROS) singlet molecular oxygen (O 2 ( 1 Δ g )), superoxide radical anion (O 2 – ), hydrogen peroxide (H 2 O 2 ) and hydroxyl radical (OH ), all photogenerated in situ through energy-transfer and electron-transfer processes. The interaction of BZ-C with O 2 ( 1 Δ g ) is essentially physical in nature and occurs with a relatively high rate constant value. The effective BZ-C degradation is mainly driven by the remaining photogenerated ROS. A comparison of the BZ and OT photooxidative-rate with those of the archetypal surface-water-contaminants aniline and phenol indicates that BZ-C degradation occurs in a moderately slower fashion than the reference contaminants, within a common overall time-scale. The primary photoprocesses initiating the Rf-sensitized degradation seems to be quite similar for the four compounds, with the simultaneous operation of Type I and Type II photoprocesses. In conclusion: the natural Rf- photosensitized degradation of BZ-C appears as a plausible process, as evaluated under simulated environmental conditions. [ABSTRACT FROM AUTHOR]

Glutathione (GSH), the most abundant biothiol in cells, not only plays a pivotal role in protective and detoxifying functions of the cell, but also serves as a very important mediator in many cellular functions. Especially, the difference of GSH level between cancer cells and normal cells is regarded as one of most important physiological parameters for cancer diagnosis. It is thereby extremely necessary to develop a simple, sensitive, and reliable analytical method for detection of GSH in cells. On the basis of the inhibition effect of GSH on the peroxidase-like activity of GSH stabilized gold nanoclusters, here a novel and facile strategy for colorimetric detection of cellular GSH level was well established. In this sensing system, GSH can effectively inhibit the oxidation of peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) to produce a blue colored product. Under the optimized conditions, the absorbance at 652 nm against GSH concentration shows a linear relationship within a range from 2 to 25 μM with detection limit of 420 nM. This excellent property allows our approach to be used to accurately evaluate the cellular GSH levels, and it is revealed that the overall GSH level in cancer cells was much higher than that in normal cells. The presented assay will enable a powerful tool for identifying cancer cells in a simple manner for biomedical diagnosis associated with GSH. [ABSTRACT FROM AUTHOR]

A novel chemo-sensor based on diaminobenzidine (H 2 L) was synthesized and characterized. The chemo-sensor shows selective “turn-on” fluorescence response to Zn 2+ ion over a variety of other competing metal ions such as Al 3+ , Mn 2+ , Fe 3+ , Co 2+ , Ni 2+ , Cu 2+ , and Cd 2+ . The strong fluorescent emission can be observed even at ppm level concentration of the probe in the presence of Zn 2+ with over 54 fold intensity enhancement at 509 nm. Similar fluorescence behaviour is also observed in a variety of solvents and solvent mixtures in the presence of zinc(II). The fluorescent emission is also detected when the H 2 L sample solution containing Zn 2+ is exposed to UV radiation. The sensitive nature of fluorescent response of the probe to Zn 2+ is gauged from the very low detection limit of 8.6 × 10 −9 M. The chemo-sensor H 2 L binds to zinc(II) in 1:1 stoichiometry as determined by Job's plot and the binding constant is calculated as 7.8 × 10 4 M −1 . [ABSTRACT FROM AUTHOR]

A new colorimetric immunosensing platform accompanying enzyme cascade amplification strategy was fabricated for quantitative screening of small-molecular mycotoxins (aflatoxin B 1 , AFB 1 used in this case) coupling with enzyme-controlled dissolution of MnO 2 nanoflakes. The visual colored assay was executed by high-efficient MnO 2 –3,3′,5,5′-tetramethylbenzidine (TMB) system (blue). In the presence of ascorbic acid, MnO 2 nanoflakes were dissolved into Mn 2+ ions, thus resulting in a perceptible color change from blue to colorless. The reaction could be weakened through ascorbate oxidase to catalyze ascorbic acid into dehydroascorbic acid, which indirectly depended on the concentration of ascorbate oxidase. By using ascorbate oxidase/ anti-AFB 1 antibody-labeled gold nanoparticles, a novel competitive-type colorimetric enzyme immunoassay was developed for detection of AFB 1 on AFB 1 -bovine serum albumin (BSA)-conjugated magnetic beads. Upon addition of target AFB 1 , the analyte competed with the conjugated AFB 1 -BSA on the magnetic beads for the labeled anti-AFB 1 antibody on the gold nanoparticles. Under optimal conditions, the absorbance decreased with increasing target AFB 1 within the dynamic range of 0.05–150 ng mL −1 with a detection limit of 6.5 pg mL −1 at the 3S blank level. The precision and specificity of the MnO 2 –TMB-based immunosensing system were acceptable. In addition, method accuracy was further validated for monitoring spiked peanut samples, giving results matched well with those obtained from commercialized AFB 1 ELISA kit. [ABSTRACT FROM AUTHOR]

[Display omitted] • CPI copolymers were prepared using 3,3′-BPDA, 4,4′-BPDA, and TFMB as the monomers. • Interchain distances increased while π-π stacking decreased with 3,3′-BPDA contents. • T g and CTE increased while mechanical properties decreased with 3,3′-BPDA contents. • Optical transparency and color intensity were improved with 3,3′-BPDA contents. • Copolymers with 20 and 40 mol% 3,3′-BPDA contents showed well-balanced properties. Colorless polyimide (CPI) copolymers were synthesized by one-step or two-step methods, using 2,2′-bis(trifluoromethyl)benzidine (TFMB), 2,2′,3,3′-biphenyltetracarboxylic dianhydride (3,3′-BPDA), and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (4,4′-BPDA) as the monomers. These polymers exhibited a d -spacing value of 5.7–6.7 Å, and their d -spacing values increased while the intensity of π-π stacking interactions decreased with the increase of 3,3′-BPDA/TFMB contents. The solubility of the copolymers were gradually enhanced as the increase of 3,3′-BPDA/TFMB contents. Their coefficients of thermal expansion and glass transition temperatures increased with 3,3′-BPDA/TFMB contents, ranging from 15 to 68 ppm K−1 and 300 to 359 °C, respectively. These polymers exhibited excellent optical transparency (λ 0 < 390 nm, T 450 > 83.2%, and b* < 4). CPI-4 and CPI-5 with 40 mol% and 20 mol% of 3,3′-BPDA/TFMB contents exhibited well-balanced solution processability and physical properties. The CPI copolymers can be potentially used in optical and optoelectronic fields owing to their desirable overall properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new strategy was designed to synthesize a new amide-based COF through the reaction between Benzidine and trimesic acid (BTC). • BTC is activated with carbonyl diimidazole (CDI), followed by its reaction with Benzidine. • The surface of synthesized COF (COF-AYLIN) is decorated via palladium (Pd) ions to synthesize Pd/COF- AYLIN. • The simulation results have suggested a multi layers of two dimensional frameworks of COF- AYLIN. • Pd/COF- AYLIN was used as a potential catalyst for the C N Coupling reaction. Among the reactions, C N coupling is one of the most important and important reactions that have taken a significant part in the industry. This study defines the design/preparation of an eco-friendly recyclable catalyst for C N coupling reaction. For this target, a new policy was designed to manufacture a new amide-based COF via the reaction amid benzidine and Benzene-1,3,5-tricarboxylic acid (BTC). BTC was activated with carbonyl diimidazole (CDI) and then reacted with benzidine for the synthesis of favorable COF (i.e., COF-AYLIN). Subsequent, the as-prepared COF was decorated via palladium ions to synthesize Pd/COF-AYLIN. The synthesized compounds were identified through the required techniques including N 2 isotherms, TEM, EDX FT-IR, XRD, SEM, ICP-OES and TG-DTA. The computer simulation results possess suggested multi sheets of the 2D framework of COF-AYLIN. Consequently, It was found that palladium ions are placed between the layers and on the COF surfaces. This nanocatalyst was used in C N Cross-Coupling reaction and showed its usage in a diverse range of different functional groups with good efficiency. The reason for introducing this catalyst system is because of its advantages such as considerably high selectivity, almost complete conversion of products, good turnover frequency (TOF), high yield, convenient separation of catalyst and product. The results show that the highest efficiency of the product in the reaction was obtained in the shortest possible time with the use of Pd/COF-AYLIN. [ABSTRACT FROM AUTHOR]

This scientifically describes a simple, cost-effective, and sensitive colorimetric method for the quantitative detection of biothiols and Hg2+ based on the peroxidase-like activity of GTP. [Display omitted] • GTP as a peroxidase-like mimic. • There is avoiding the synthesis of nanomaterials. • A facile colorimetric strategy for biothiols and Hg2+ detection has been established. Guanosine-5′-triphosphate (GTP) not only plays a key role in a majority of cellular processes but also be proposed as a peroxidase-like mimic. Compared with nanozymes, GTP shows good tolerance under harsh conditions, which can be used to construct an easy colorimetric analysis for the detection of biomolecules. Here, on the basis of the peroxidase-like activity of GTP which can catalyze the oxidation of 3,3′,5,5′-tetramethyl benzidine dihydrochloride (TMB), colorimetric sensing was established for biothiols and Hg2+. Biothiols reduced the oxTMB back to colorless TMB, and Hg2+ restored the formation of oxTMB, leading to the recovery of color. This method not only provides a platform for the detection of metal ions and biothiols, but also shows that GTP has great potential for analytical detection. [ABSTRACT FROM AUTHOR]

3, 3′, 5, 5′-tetramethylbenzidine (TMB) has been widely used as a chromogenic substrate for colorimetric immunoassays. Normally, the colorless TMB is oxidized into yellow TMB 2+ (in acidic solution) to indicate the presence of the target molecules. However, this kind of monochromic intensity changes seriously confine the accuracy of visual inspection. Herein, we demonstrate for the first time that TMB 2+ can quantitatively and efficiently etch gold nanorods (AuNRs). The addition of AuNRs into a solution containing different amount of TMB 2+ generates vivid color responses as colorful as a rainbow, and the etching process can be finished within 90 s. As a result, the exact concentration of TMB 2+ can be easily distinguished with the naked eyes by the corresponding solution color. Based on this finding, we incorporate AuNRs into the well-developed, commercially available horseradish peroxidase (HRP)-TMB immunoassay system, so that it can be utilized for semiquantitative detection of a broad range of disease biomarkers with the naked eyes (termed ‘NEQ-IA’). Carcinoembryonic antigen (CEA) and Prostate specific antigen (PSA) had been chosen as example targets to test the feasibility of the proposed biosensor. The results showed good accordance with the conventional methods. Because no sophisticated apparatus but human eyes are used as the readout, the proposed NEQ-IA could be a good supplementary to current state-of-the-art immunoassay methods for those applications that require the use of portable and affordable devices, for example, for the detection of disease biomarkers at home and in the field. [ABSTRACT FROM AUTHOR]

Benzidine, a compound bearing aromatic rings and terminal amino groups, was employed for the intercalation and simultaneous reduction of graphite oxide (GO). The aromatic diamine can be intercalated into GO as follows: (1) by grafting with the epoxy groups of GO, (2) by hydrogen bonding with the oxygen containing groups of GO. Stacking between benzidine aromatic rings and unoxidized domains of GO may occur through π-π interaction. The role of benzidine is influenced by pH conditions and the weight ratio GO/benzidine. Two weight ratios were tested i.e. 1:2 and 1:3. Under strong alkaline conditions through K 2 CO 3 addition (pH ∼10.4–10.6) both intercalation and reduction of GO via amino groups occur, while under strong acidic conditions through HCl addition (pH ∼1.4–2.2) π-π stacking is preferred. When no base or acid is added (pH ∼5.2) and the weight ratio is 1:2, there are indications that reduction and π-π stacking occur, while at a GO/benzidine weight ratio 1:3 intercalation via amino groups and reduction seem to dominate. The aforementioned remarks render benzidine a multifunctional tool towards production of reduced graphene oxide. The effect of pH conditions and the GO/benzidine weight ratio on the quality and the electrochemical properties of the produced graphene-based materials were investigated. Cyclic voltammetry measurements using three-electrode cell and KCl aqueous solution as an electrolyte gave specific capacitance values up to ∼178 F/g. When electric double-layer capacitors (EDLC) were fabricated from these materials, the maximum capacitance in organic electrolyte i.e., tetraethyl ammonium tetrafluoroborate (TEABF 4 ) in polycarbonate (PC) was ∼29 F/g. [ABSTRACT FROM AUTHOR]

Fluorinated polyimide (PI) consisting of 2,2-bis(3,4-anhydrodicarboxyphenyl)-hexafluoropropane (6FDA) and 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (TFDB) were deposited on silicon wafers with patterned microscale trenches. The deposition was carried out in supercritical carbon dioxide (scCO 2 ) with 5 mol% N , N -dimethylformamide (DMF). The effects of the monomer concentration and deposition temperature on the deposition of fluorinated PI inside the microscale trenches were studied to clarify the appropriate conditions for the deposition of fluorinated PI using scCO 2 . The monomer concentration and deposition temperature studied were in the ranges of 0.28 × 10 −2 –1.1 × 10 −2 mol/dm 3 and 150–250 °C, respectively. The amount of deposited fluorinated PI inside the trenches increased with increasing monomer concentrations and deposition temperature. Moreover, the time course of the phase behavior in the reactor was also investigated during the deposition, and the time-dependent changes in the shapes and amount of deposited fluorinated PI inside the microscale trenches were also investigated. Finally, the relationship between the trench size and the deposition behavior was studied, and the trenches of width-depth sizes of 1.5–23.5, 3–26, and 5–30 μm could be completely filled with fluorinated PI simultaneously. [ABSTRACT FROM AUTHOR]

Electrochemical tools are important biosensor platforms for disease diagnosis, due to their speediness, easiness, low cost and portability. However, for DNA detection, the use of indicators and/or intercalators is necessary to improve electrochemical sensitivity. Currently, ethidium bromide (EthBr) is the cheapest and most used DNA intercalators, but presents carcinogenic and teratogenic properties. Other indicators may be important for DNA photonic detection, and besides being more expensive, they behave similarly to EthBr. This investigation shows for the first time the use of tetramethylbenzidine(TMB) as a new remarkable non-carcinogenic DNA indicator for genosensing purposes, which may be used for nucleic acid detection of microorganisms, based on complementarity of base-pairing between probe and target molecules. The results indicate that TMB can be used as a new electrochemical indicator readily applicable in genosensors, which is able to detect the hybridization of single stranded DNA probe with its complementary target strand. An additional advantage of TMB, beside its non-genotoxicity, is the electrochemical reduction property, which prevents interference of serum components and other oxidative samples in the electrochemical analysis. [ABSTRACT FROM AUTHOR]

A novel and non-polymeric anion-inserting electrode material has been designed and prepared for promoting research on molecular ion rechargeable batteries: 5,12-diaminorubicene (DARb). The apolar core structure of a rubicene molecule has been coupled to two amino-groups for producing an original conjugated primary diamine exhibiting low affinity for polar solvents such as common carbonate-based battery electrolytes. The electrochemical reactivity of this organic molecule has been probed in a dual-ion cell configuration (vs. Li) using six different electrolyte formulations in terms of solvent (PC, EC-DMC) and lithium salt (LiPF 6 , LiClO 4 , LiTFSI). This diamino-rubicene material systematically showed a reversible electroactivity and promising performances when using 1 M LiPF 6 in EC:DMC (1:1 vol.%) as the electrolyte, such as an average potential of ~ 3.4 V vs. Li + /Li 0 , an initial capacity of 115 mAh·g − 1 and a good capacity retention over 60 cycles without any optimization. [ABSTRACT FROM AUTHOR]

It was found that reduced state carbon dots (r-CDs) possessed intrinsic peroxidase-like activity, and could catalytically oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) by H 2 O 2 to produce a color reaction. The effects of temperature, pH, incubating time and the concentration of H 2 O 2 and TMB on catalytic activity of r-CDs were investigated. Finally we calculated the kinetic constant was ca. 0.00729 min −1 and applied r-CDs to glucose sensing by coupling glucose oxidase. As low as 2 µM H 2 O 2 could be detected with a linear range from 0.010 to 0.40 mM via this method. This study offered a simple, sensitive, and high selectivity method for glucose determination even in serum. [ABSTRACT FROM AUTHOR]

Separation of complex gas mixtures, such as natural gas using polymer membranes, often involves components with a wide range of condensabilities and propensity to interact with the polymer, potentially changing the transport properties of all components. There are few studies of such phenomena in the open literature. Here, the influence of toluene, a surrogate aromatic contaminant in natural gas, on pure and mixed CO 2 and CH 4 gas transport properties at 35 °C was investigated for a thermally rearranged (TR) polymer prepared from a polyimide precursor based on 3,3′-dihydroxy-4,4′-diamino-biphenyl (HAB) and 2,2′-bis-(3,4-dicarboxy-phenyl) hexafluoropropane dianhydride (6FDA). As the polymer was exposed to CO 2 , CH 4 , and their equimolar mixture, at a toluene activity of about 0.3, CO 2 and CH 4 permeability coefficients decreased by more than 90% relative to their respective pre-exposure values due to antiplastization and competitive sorption. CO 2 /CH 4 selectivity went through a maximum as toluene activity increased, reflecting the interplay between competitive sorption, antiplasticization, and plasticization. The recovery of gas permeation properties was explored by measuring CO 2 and CH 4 permeabilities after removing toluene from the feed. These effects were largely reversed when toluene was removed from the feed gas mixture. Toluene vapor sorption was determined as a function of toluene activity, and the sorption data were used to help rationalize the changes in CO 2 and CH 4 gas permeability coefficients in the presence of toluene. A qualitative assessment of antiplasticization and competitive sorption effects was provided using the partial-immobilization dual mode model. [ABSTRACT FROM AUTHOR]

An ultrasensitive colorimetric assay for Hg 2+ detection was presented based on synergistic catalytic effect of gold nanoparticles (AuNPs) and Hg. The AuNPs could catalyze the reduction of Hg 2+ by surface-capping citrate. The effect of Hg 2+ uptake implied amalgam formation and increased the surface area of AuNPs, leading to remarkable catalytic amplification of the peroxidase-like activity of AuNPs. On the basis of this effect, 3,3′,5,5′-tetramethylbenzidine (TMB) as colorimetric probes could be catalyzed into a black blue product in the presence of H 2 O 2 . The detection limit of the colorimetric assay for Hg 2+ is 0.1 nM. Furthermore, the detection limit of Hg 2+ in river water samples and tap water samples are 0.66 nM, and 0.43 nM, respectively. The results are far below the World Health Organization (WHO) permissible limit (30 nM). The assay is highly sensitive, specific, and able to detect Hg 2+ rapidly without requiring sophisticated equipment. In addition, our strategy could also be used as a promising and convenient approach for detection of the target in environmental protection. [ABSTRACT FROM AUTHOR]

When treated with dilute inorganic acids N , N ′-diarylhydrazines (hydrazobenzenes) with an alkyl substituent in the 4-position undergo [5,5]-sigmatropic rearrangement reactions to furnish 4-(4′-aminophenyl)-4-alkylcyclohexa-2,5-dienimines ( ipso -benzidines) in moderate to excellent yields. Steric bulk of the 4-alkyl substituent in the starting material decreases the yield of the respective ipso -benzidine. Additional electron-donating alkyl substituents in the ortho - and/or meta -positions on both rings generally promote the reaction and consequently increase the yield of the 4.4′-benzidine rearrangement product. Described herein are our findings regarding the scope and limits of this unusual benzidine rearrangement. [ABSTRACT FROM AUTHOR]