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In this work, an efficient and universal streptavidin-functionalized nitrogen-doped graphene (NG) was for the first time proposed and used to develop a highly sensitive electrochemical immunosensor for the detection of tumor markers. Transmission electron microscopy, electrochemical impedance spectrum, static water contact measurement, and cyclic voltammetry were used to characterize the streptavidin-functionalized NG platform and immunosensor. The biofunctionalized NG showed excellent hydrophilicity, larger specific surface area, and high electrochemical activity. These properties of the platform enhanced the loading capacity of proteins, and retained the bioactivity of the immobilized proteins, and thus remarkably improved the sensitivity of the immunosensor. Using carcinoembryonic antigen (CEA) as model analyte, the proposed immunosensor demonstrated a wide linear range of 0.02–12 ng mL −1 with a low detection limit of 0.01 ng mL −1 . The CEA immunosensor could be applied to detect human serum samples with satisfactory results. The streptavidin-functionalized NG material provided an universal and promising platform for the electrochemical immunosensing applications. [ABSTRACT FROM AUTHOR]

Chicken interleukin-4 (ChIL-4), which is released by activated type 2 helper (Th2) cells following their stimulation in vitro, is an important indicator for the study of cell-mediated immunity in chickens after infection or vaccination. In this work, the first ChIL-4 chemiluminescent (CL) immunosensor was developed via the immobilization of monoclonal ChIL-4 antibodies on a nitrogen-doped graphene (NG)-chitosan nanocomposite matrix. NG nanosheets were used for the first time in the CL immunoassay to provide a biocompatible microenvironment for the immobilized capture antibody. The ChIL-4 immunosensor was characterized systematically. The proposed immunosensor displayed a wide linear range from 0.05 to 70 ng mL −1 and a low detection limit of 0.02 ng mL −1 at a signal-to-noise ratio of 3. Compared to traditional assay methods, this system was more flexible, simple, rapid, and sensitive. Moreover, this CL immunoassay system had an excellent detection and fabrication reproducibility, a high specificity, an acceptable accuracy, and a high stability. This work enables the specific detection of ChIL-4 and the further study of its role in the immune responses of poultry. [ABSTRACT FROM AUTHOR]

In this work, we reported an efficient platinum nanoparticles functionalized nitrogen doped graphene (PtNPs@NG) nanocomposite for devising novel electrochemical glucose biosensor for the first time. The fabricated PtNPs@NG and biosensor were characterized using transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, static water contact angle, UV–vis spectroscopy, electrochemical impedance spectra and cyclic voltammetry, respectively. PtNPs@NG showed large surface area and excellent biocompatibility, and enhanced the direct electron transfer between enzyme molecules and electrode surface. The glucose oxidase (GOx) immobilized on PtNPs@NG nanocomposite retained its bioactivity, and exhibited a surface controlled, quasi-reversible and fast electron transfer process. The constructed glucose biosensor showed wide linear range from 0.005 to 1.1 mM with high sensitivity of 20.31 mA M −1 cm −2 . The detection limit was calculated to be 0.002 mM at signal-to-noise of 3, which showed 20-fold decrease in comparison with single NG-based electrochemical biosensor for glucose. The proposed glucose biosensor also demonstrated excellent selectivity, good reproducibility, acceptable stability, and could be successfully applied in the detection of glucose in serum samples at the applied potential of −0.33 V. This research provided a promising biosensing platform for the development of excellent electrochemical biosensors. [ABSTRACT FROM AUTHOR]

Bovine interferon gamma (BoIFN-γ) released by T cells plays very important roles in early diagnosis of Mycobacterium tuberculosis (MTB) infections and control of bovine tuberculosis. In this work, a label-free electrochemical impedance immunosensor is for the first time developed for highly sensitive determination of BoIFN-γ. Cylinder-shaped TiO 2 nanorods are synthesized by a facile hydrothermal method, and show high surface area and good hydrophicility. The immunosensor is fabricated by the immobilization of BoIFN-γ monoclonal antibody on the TiO 2 nanorods modified glassy carbon electrode. The prepared TiO 2 and immunosensor are characterized using transmission electron microscopy, scanning electron microscopy, X-ray diffraction, contact angle measurement, cyclic voltammetry, and electrochemical impedance spectra. The BoIFN-γ concentration is measured through the relative increase of impedance values in corresponding specific binding of BoIFN-γ antigen and BoIFN-γ antibody. The relative increased impedance values are proportional to the logarithmic value of BoIFN-γ concentrations in a wide range of 0.0001 to 0.1 ng/mL with a low detection limit of 0.1 pg/mL. The developed BoIFN-γ immunosensor shows a 249-fold decrease in detection limit in comparison with current enzyme-linked immunosorbent assay. This study provides a new, simple, and highly sensitive approach for very potential application in early diagnosis of MTB infections and control of bovine tuberculosis. [ABSTRACT FROM AUTHOR]

A tetragonal columnar-shaped TiO2 (TCS-TiO2) nanorods are synthesized via a facile route for the immobilization of glucose oxidase (GOx). A novel electrochemical glucose biosensor is constructed based on the direct electrochemistry of GOx at TCS-TiO2 modified glassy carbon electrode. The fabricated biosensor is characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, electrochemical impedance spectra and cyclic voltammetry. The immobilized enzyme molecules on TCS-TiO2 nanorods retain its native structure and bioactivity and show a surface controlled, quasi-reversible and fast electron transfer process. The TCS-TiO2 nanorods have large surface area and provide a favorable microenvironment for enhancing the electron transfer between enzyme and electrode surface. The constructed glucose biosensor shows wide linear range from 5.0×10−6 to 1.32×10−3 M with a high sensitivity of 23.2mAM−1 cm−2. The detection limit is calculated to be 2.0×10−6 M at signal-to-noise of 3. The proposed glucose biosensor also exhibits excellent selectivity, good reproducibility, and acceptable operational stability. Furthermore, the biosensor can be successfully applied in the detection of glucose in serum sample at the applied potential of −0.50V. The TCS-TiO2 nanorods provide an efficient and promising platform for the immobilization of proteins and development of excellent biosensors. [ABSTRACT FROM AUTHOR]

Abstract: The quantitative detection of chicken interferon-γ (ChIFN-γ) released by T cells after in vitro stimulation is a good evaluation of cell-mediated immunity in chickens after infection or vaccination. This work reports a new flow-through the chemiluminescent (CL) immunoassay method for rapid and specific determination of ChIFN-γ at a level of sub-picogram per milliliter. The biocompatible graphene oxide nanosheet is introduced into CL immunoassay for highly efficient immobilization of capture antibody. The detection limit of the proposed method at a signal to noise ratio of 3 is 0.36pgml−1, which is 138-fold lower than the current lowest value of 50pgml−1 for ChIFN-γ. Coupling with a flow-through system, the whole immunoassay process can be completed within 25min. The resulting ChIFN-γ immunosensor shows excellent detection and fabrication reproducibility, good specificity and stability. The assay results of nature ChIFN-γ samples with the proposed method are in an acceptable agreement with the reference values. Compared to the present assay methods, this method is more flexible, simple, rapid and sensitive. The aim of this work is to demonstrate that the ultrasensitive, specific and rapid CL immunoassay format can become a very potential application for quantifying ChIFN-γ and further studying its role in immune response in poultry. [Copyright &y& Elsevier]

Highlights: [•] An ultrasensitive chemiluminescent (CL) immunoassay strategy was developed. [•] This assay was preformed based on a streptavidin-functionalized MWCNTs platform. [•] The sensitivity displays 7.9-fold increase compared to that without MWCNTs. [•] This method provides a promising approach for ultrasensitive CL immunoassay. [Copyright &y& Elsevier]

Abstract: Multi-walled carbon nanotubes (MWCNTs)–nanoflake-like SnS2 nanocomposite were designed for immobilization of glucose oxidase (GOx). The direct electrochemistry of GOx and glucose sensing at MWCNTs–SnS2 modified glassy carbon electrode were studied. Compared with single MWCNTs or SnS2, the MWCNTs–SnS2 film has larger surface area and provides a more favorable microenvironment for facilitating the electron transfer between enzyme and electrode surface. The properties of GOx/MWCNTs–SnS2 were examined by scanning electron microscopy, UV–vis spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry. The immobilized enzyme on MWCNTs–SnS2 composite film retained its native structure and bioactivity and showed a surface controlled, reversible two-proton and two-electron transfer reaction with a apparent electron transfer rate constant of 3.96s−1. The constructed glucose biosensor exhibits wider linear range from 2.0×10−5 M to 1.95×10−3 M, much lower detection limit of 4.0×10−6 M at signal-to-noise of 3 and higher sensitivity of 21.65mAM−1 cm−2 than our previous nanoflake-like SnS2-based glucose sensor. The proposed biosensor has excellent selectivity, good reproducibility, and acceptable operational stability and can be successfully applied in the reagentless glucose sensing at −0.43V. This MWCNTs–SnS2 composite provides a new avenue for immobilizing proteins and fabricating excellent biosensors. [Copyright &y& Elsevier]

Abstract: A novel urchin-like In2O3–chitosan modified glassy carbon electrode (GCE) is for the first time prepared. The direct electrochemistry of glucose oxidase (GOD) immobilized on the surface of modified GCE and biosensing are studied. The urchin-like In2O3 nanostructure-based matrix has large specific surface area and provides a favorable and biocompatible microenvironment for promoting the direct electron transfer between proteins and electrode surface. The properties of different modified electrode are characterized by scanning electron microscopy (SEM), electrochemical impedance spectra (EIS), UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry, respectively. The constructed glucose biosensor shows wide linear range (5.0×10−6 to 1.3×10−3 M), low detection limit (1.9×10−6 M), a Michaelis–Menten constant of 0.37mM. The proposed biosensor has good sensitivity, excellent selectivity, good reproducibility and stability. This urchin-like In2O3–chitosan matrix provides a new approach and efficient matrix for the direct electrochemistry of proteins and developing novel types of biosensors. [Copyright &y& Elsevier]

Abstract: A streptavidin functionalized capillary immune microreactor was designed for highly efficient flow-through chemiluminescent (CL) immunoassay. The functionalized capillary could be used as both a support for highly efficient immobilization of antibody and a flow cell for flow-through immunoassay. The functionalized inner wall and the capture process were characterized using scanning electron microscopy. Compared to conventional packed tube or thin-layer cell immunoreactor, the proposed microreactor showed remarkable properties such as lower cost, simpler fabrication, better practicality and wider dynamic range for fast CL immunoassay with good reproducibility and stability. Using α-fetoprotein as model analyte, the highly efficient CL flow-through immunoassay system showed a linear range of 3 orders of magnitude from 0.5 to 200ngmL−1 and a low detection limit of 0.1ngmL−1. The capillary immune microreactor could make up the shortcoming of conventional CL immunoreactors and provided a promising alternative for highly efficient flow-injection immunoassay. [Copyright &y& Elsevier]

Abstract: A novel biosensor is developed based on immobilization of proteins on nanoflake-like SnS2 modified glass carbon electrode (GCE). With glucose oxidase (GOD) as a model, direct electrochemistry of the GOD/nanoflake-like SnS2 is studied. The prepared SnS2 has large surface area and can offer favorable microenvironment for facilitating the electron transfer between protein and electrode surface. The properties of GOD/SnS2 are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV), respectively. The immobilized enzyme on nanoflake-like SnS2 retains its native structure and bioactivity and exhibits a surface-controlled, reversible two-proton and two-electron transfer reaction with the apparent electron transfer rate constant (k s) of 3.68s−1. The proposed biosensor shows fast amperometric response (8s) to glucose with a wide linear range from 2.5×10−5 M to 1.1×10−3 M, a low detection limit of 1.0×10−5 M at signal-to-noise of 3 and good sensitivity (7.6±0.5mAM−1 cm−2). The resulting biosensor has acceptable operational stability, good reproducibility and excellent selectivity and can be successfully applied in the reagentless glucose sensing at −0.45V. It should be worthwhile noting that it opens a new avenue for fabricating excellent electrochemical biosensor. [Copyright &y& Elsevier]

Abstract: A novel system of series-wound immunosensing channels (SWIC) was proposed for automated chemiluminescent (CL) dual-analyte immunoassay by immobilizing respectively different capture antibodies on the inner walls of series-wound glass channels. This system could use a single enzyme as label to perform multiplex immunoassay in one fluid way. Using α-fetoprotein (AFP) and carcinoembryonic antigen (CEA) as model analytes, the mixture including AFP, horseradish peroxidase (HRP)-labeled anti-AFP antibody, CEA and HRP-labeled anti-CEA antibody was introduced into the SWIC for carrying out the on-line incubation. Upon injection of CL substrate the CL signals from the two immunosensing channels were conveniently resolved and near-simultaneously collected with the aid of optical shutter. AFP and CEA could be rapidly assayed in the ranges of 1.0–100 and 1.0–80ng/ml with detection limits of 0.41 and 0.39ng/ml, respectively. The assay results of clinical serum samples were in an acceptable agreement with the reference values. This designed flow-through immunosensing system based on SWIC provided an automated, reusable, simple, sensitive and low-cost approach for multianalyte immunoassay. [ABSTRACT FROM AUTHOR]

Abstract: A novel immunoaffinity column used as an immunosensor for flow-injection chemiluminescent (CL) immunoassay was prepared by immobilizing antibody on carboxylic resin beads. The immunosensor could fast recognize and trap the immunocomplex of horseradish peroxidase (HRP)-labeled antibody and antigen, which was firstly formed with a micro-bubble accelerated pre-incubation process, to produce a sandwich immunocomplex. The HRP introduced in the immunoaffinity column could catalyze the CL reaction to produce enzyme-enhanced emission. With α-fetoprotein (AFP) as a mode, a flow-injection CL immunoassay was proposed. The whole assay for one sample, including the pre-incubation and the regeneration of immunoaffinity column, could be performed within 16min. The linear range was 1.0–80ng/ml with a correlation coefficient of 0.998 and a detection limit of 0.1ng/ml at a signal/noise ratio of 3. The intra- and inter-assay coefficients of variation at 20ng/ml AFP were 1.2% and 8.5%, respectively. The storage stability of the immunoaffinity column and the accuracy for sample detection were acceptable. This flexible, sensitive, low-cost, and rapid method is valuable for clinical immunoassay. [Copyright &y& Elsevier]

Abstract: Treatment of halides 5 with electrophilic alkenes 2 afforded the corresponding dihydrofurans 3 and 4 in the presence of 1, 4-diazabicyclo[2.2.2]octane (DABCO) with good to excellent yields and in a stereoselective manner in most cases. Moreover, the stereoisomers 3 and 4 could be easily transformed each other in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). [Copyright &y& Elsevier]

Abstract: A mesoporous silica nanoshpere (MSN) was proposed to modify glassy carbon electrode (GCE) for the immobilization of protein. Using glucose oxidase (GOD) as a model, direct electrochemistry of protein and biosensing at the MSN modified GCE was studied for the first time. The MNS had large surface area and offered a favorable microenvironment for facilitating the direct electron transfer between enzyme and electrode surface. Scanning electron microscopy, transmission electron microscopy, UV–vis spectroscopy and cyclic voltammetry were used to examine the interaction between GOD and the MSN matrix. The results demonstrated that the immobilized enzyme on the MSN retained its native structure and bioactivity. In addition, the electrochemical reaction showed a surface controlled, reversible two-proton and two-electron transfer process with the apparent electron transfer rate constant of 3.96s−1. The MNS-based glucose biosensor exhibited the two linear ranges of 0.04–2.0mM and 2.0–4.8mM, a high sensitivity of 14.5mAM−1 cm−2 and a low detection limit of 0.02mM at signal-to-noise of 3. The proposed biosensor showed excellent selectivity, good reproducibility, acceptable stability and could be successfully applied in the reagentless detection of glucose in real samples at −0.45V. The work displayed that mesoporous silica nanosphere provided a promising approach for immobilizing proteins and fabrication of excellent biosensors. [Copyright &y& Elsevier]

Abstract: An ultrasensitive electrochemical method for simultaneous determination of lead and cadmium was first developed using the novel bismuth–Nafion-medical stone doped disposable electrode (an improved wax-impregnated graphite electrode). Through the synergistic sensitization effect of the resulting composite material, the disposable electrode showed remarkable electrochemical responses to lead and cadmium. The oxidation of the two metals produced two well-defined and separated square wave peaks at about −0.62V for Pb2+ and −0.85V for Cd2+, respectively. The effects of the amount of medical stone, concentration of Nafion, thickness of bismuth, pH of buffer solution, deposition potential, accumulation time, voltammetric measurement and possible interferences were investigated in detail. Under the optimal conditions, the fabricated electrode exhibited linear ranges from 2.0 to 12.0μgL−1 with detection limit of 0.07μgL−1 for lead and 2.0–12.0μgL−1 with detection limit of 0.47μgL−1 for cadmium. The assay results of heavy metals in wastewater with the proposed method were in acceptable agreement with the atomic absorption spectroscopy method. [Copyright &y& Elsevier]

Abstract: A new method has been established for the determination of dopamine hydrochloride (DPH) using sodium 1,2-naphthoquinone-4-sulfonate (NQS) and tetradecyl benzyl dimethyl ammonium chloride (Zeph). This method is based on the formation of a pink compound from the reaction of DPH, sodium 1,2-naphthoquinone-4-sulfonate and Zeph. The condensation reaction proceeds quantitatively in pH 9.40 buffer solution. The maximum absorption wavelength and the value of ɛ 491 were 491nm, and 7.51×103 lmol−1 cm−1, respectively, when the stoichiometric ratio of the reaction was 1:1:1. Beer′s law was obeyed in the range of 0.16–40mgl−1 of DPH. The data have been filled to a linear regression equation A =0.5781+0.0254 C (mgl−1), with a correlation coefficient of 0.9993. The detection limit is 0.12mgl−1, R.S.D. is 0.64% (40mgl−1, n =11), and average recovery is over 99.7%. This paper further improves the determination of DPH compared to the previous methods. The kinetic property and reaction mechanism have also been discussed. This proposed method has been successfully applied to the determination of DPH in injection and biological samples with satisfactory results. [Copyright &y& Elsevier]

• The crack morphology and trend were basically the same. • The boss of blade root is worn seriously in case of the turbine axial offset of the unit with an anomalous are. • FEM analysis indicates that the upper part of the first tooth on the steam outlet side of the blade root is the maximum centrifugal stress part. • The leaf root not tightly installed is the main cause of the accident. An analysis of the fracture cause for a steam turbine blade root is conducted in this study. During the maintenance of a steam turbine, nineteen IP-6S (Intermediate Pressure 6th Stage) blades with root cracks were detected. The causes of blade cracking are analyzed through macroscopic inspection, magnetic particle testing, room temperature mechanical property testing, micro-hardness testing, chemical analysis, metallo-graphic analysis, scanning electron microscopy and energy spectrum analysis, as the blade static stress is simulated in this paper. The results showed that the chemical composition and mechanical properties of the blade leaves are qualified, and none abnormal corrosive substances are found in the crack initiation part. The numerical simulation result showed that the surface of the first tooth arc is the mostly stressed part of the root, and the stress level can be increased by a loosing installation. The main reason for the root cracking of the blade is that the gap between the blade root and the leaf groove becomes larger, which leads to the changes of the blade root contact mode, then the stress of the first tooth arc was further increased, finally the root and leaf groove wear is aggravated, and fatigue cracking occurs at the stressed first tooth. [ABSTRACT FROM AUTHOR]

Abstract Quantitative detection of multiple chicken cytokines is a good evaluation of cell-mediated immunity in chickens after disease infection or vaccination. However, current assay methods for chicken cytokines cannot meet the needs of clinical diagnosis due to unsatisfactory sensitivity and low assay throughput. Herein, a sensitive chemiluminescence (CL) imaging immunosensor array has been developed for high-throughput detection of multiple chicken cytokines. The chicken cytokines immunosensor array was prepared by assembling different cytokine capture antibodies onto a disposable silanized glass chip, where horseradish peroxidase and antibody-conjugated gold nanoparticles were used as multienzymatic amplification probe for CL imaging signal amplification. By using a sandwich assay mode, the amplified CL signals from each sensing array cell were collected for quantitation. Using chicken interleukin-4 and chicken interferon-γ as model cytokines, this novel multiplexed and amplified method demonstrated simultaneous measurement of the two chicken cytokines in the linear ranges of 0.008–0.12 ng/mL and 0.005–0.20 ng/mL, respectively, which yields limits of detection down to 2 pg/mL and 3 pg/mL. The CL imaging array method reported here also demonstrated high specificity, good repeatability, and high stability and accuracy, providing a novel multiplex immunoassay strategy for highly sensitive and high-throughput detection of chicken cytokines and further disease diagnosis in poultry. Graphical abstract A novel multiplex immunosensor array for sensitive and high-throughput detection of multiple chicken cytokines is for the first time developed based on highly-sensitive chemiluminescence imaging coupled with a multienzymatic signal amplification probe. Image 1 Highlights • Multiplex immunosensor array for chicken cytokines was proposed for the first time. • Multiple chicken cytokines were simultaneously detected by sensitive CL imaging system. • The multiplex cytokines immunoassay has much better performance compared with current methods. • This work provides a novel strategy for sensitive and high-throughput multiplex immunoassay. [ABSTRACT FROM AUTHOR]

Effective enhancement of the separation and transfer of photogenerated electrons and holes of semiconductor photocatalysts is key to increase their photocatalytic efficiency. This study aims at improving the photocatalytic performance of visible-light-responsive, CdI 2 -type layered SnS 2 by employing good conductivity N-doped reduced graphene oxide (NRG) and polyaniline (PANI) as the receptors and transporters of photogenerated electrons and holes, respectively. PANI/SnS 2 /NRG ternary composites were prepared by a three-step method, and the optimum conditions for preparing the most efficient product were explored. The photocatalytic experiments demonstrated that the PANI/SnS 2 /NRG ternary composite prepared under the optimum conditions (PANI/SnS 2 /NRG-2%) had markedly higher photocatalytic activity than SnS 2 nanoplates, SnS 2 /PANI and SnS 2 /NRG binary composites in the reduction of aqueous Cr(VI) under the irradiation of visible-light (λ > 420 nm). Based on comparison of the photoabsorption, photoluminescence and electrochemical impedance properties of PANI/SnS 2 /NRG, SnS 2 /PANI and SnS 2 , it was thought that the coupling of SnS 2 with both PANI and NRG had synergistic effects in increasing the absorption of visible-light as well as the separation and transfer of photogenerated electrons and holes, which contributed to the exceptionally high photocatalytic activity of PANI/SnS 2 /NRG ternary composite. Moreover, it was discovered that the photocatalytic reduction of Cr(VI) over PANI/SnS 2 /NRG-2% was dominantly through the reduction by photogenerated electrons, whereas both photogenerated electron and superoxide anion radical (O 2 – ) reduction played important roles in the photocatalytic reduction of Cr(VI) over SnS 2 . Besides, the influences of photocatalytic testing conditions (including starting pH and concentration of Cr(VI) solution, and dosage of photocatalyst) on the efficiency of PANI/SnS 2 /NRG-2% in treatment of aqueous Cr(VI) were also examined. [ABSTRACT FROM AUTHOR]

Dual-functional cupric oxide nanorods (CuONRs) as peroxidase mimics are proposed for the development of a flow-through, label-free chemiluminescent (CL) immunosensor. Forming the basis of this cost-efficient, label-free immunoassay, CuONRs, synthesized using a simple hydrothermal method, were deposited onto epoxy-activated standard glass slides, followed by immobilization of biotinylated capture antibodies through a streptavidin bridge. The CuONRs possess excellent catalytic activity, along with high stability as a solid support. Antigens could then be introduced to the sensing system, forming large immunocomplexes that prevent CL substrate access to the surface, thereby reducing the CL signal in a concentration dependent fashion. Using carcinoembryonic antigen (CEA) as a model analyte, the proposed label-free immunosensor was able to rapidly determine CEA with a wide linear range of 0.1–60 ng mL −1 and a low detection limit of 0.05 ng mL −1 . This nanozyme-based immunosensor is simple, sensitive, cost-efficient, and has the potential to be a very promising platform for fast and efficient biosensing applications. [ABSTRACT FROM AUTHOR]

In this work, SrTiO 3 nanoparticles (SrTiO 3 NPs), a novel and effective perovskite-type material, are synthesized to modify electrode for the development of sensitive enzymatic electrochemical biosensor applications. The electrochemical behavior of glucose oxidase (GOx) immobilized on SrTiO 3 NPs-modified glassy carbon electrode is investigated. Scanning electron microscopy and cyclic voltammetry are used to characterize the morphology and assay property of different modified electrodes. Results illustrate that SrTiO 3 NPs possess large surface area and apparently enhance the direct electron transfer between GOx and modified electrode. The SrTiO 3 NPs-based enzyme biosensor shows a high sensitivity of 15.6 mA·M − 1 ·cm − 2 , wide linear range from 0.01 mM to 1.2 mM, and a low detection limit of 3 μM (S/N = 3). Furthermore, the resultant glucose biosensor has excellent selectivity, acceptable repeatability, practicality and stability. The perovskite SrTiO 3 NPs provide a very attractive and potential electrode material to develop electrochemical biosensors. [ABSTRACT FROM AUTHOR]

In this work, novel perovskite-type calcium titanate nanoparticles (CaTiO 3 NPs) were for the first time exploited for the immobilization of proteins and the development of electrochemical biosensor. The CaTiO 3 NPs were synthesized with a simple and cost-effective route at low temperature, and characterized by scanning electron microscopy, X-ray photoelectron spectroscopic spectrum, electrochemical impedance spectrum, UV–visible spectroscopy, Fourier transform infrared spectrum, and cyclic voltammetry, respectively. The results indicated that CaTiO 3 NPs exhibited large surface area, and greatly promoted the direct electron transfer between enzyme molecules and electrode surface. The immobilized enzymes on this matrix retained its native bioactivity and exhibited a surface controlled, quasi-reversible two-proton and two-electron transfer reaction with an electron transfer rate of 3.35 s −1 . Using glucose oxidase as model, the prepared glucose biosensor showed a high sensitivity of 14.10±0.5 mA M −1 cm −2 , a wide linear range of 7.0×10 −6 to 1.49×10 −3 M, and a low detection limit of 2.3×10 −6 M at signal-to-noise of 3. Moreover, the biosensor also possessed good reproducibility, excellent selectivity and acceptable storage life. This research provided a new-type and promising perovskite nanomaterials for the development of efficient biosensors. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis of a new high efficiency visible-light photocatalyst made of SnS 2 and conjugated derivative (CPVA) from thermal dehydration of polyvinyl alcohol (PVA), and the evaluation of its performance in photocatalytic reduction of aqueous Cr(VI). SnS 2 /CPVA nanocomposites were synthesized via the procedures of (i) mixing of SnS 2 nanocrystals and PVA in aqueous solution and evaporation of the aqueous solvent to generate SnS 2 /PVA nanocomposites, and (ii) thermal treatment of the SnS 2 /PVA nanocomposites for transforming their PVA into conjugated CPVA. The optimum conditions for synthesis of most efficient SnS 2 /CPVA nanocomposite were explored. The characterization by X-ray diffraction, Raman spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, high resolution transmission electron microscopy and elemental mapping indicated the formation of SnS 2 /CPVA nanocomposites. The photocatalytic experiments showed that SnS 2 /CPVA nanocomposite synthesized under the optimum conditions (SnS 2 /CPVA-1%-180 °C-2 h) had exceptionally higher photocatalytic activity than SnS 2 nanocrystals, physical mixture of SnS 2 nanocrystals and CPVA, SnS 2 /CPVC nanocomposite and TiO 2 /CPVA nanocomposite in the reduction of aqueous Cr(VI) under visible-light (wavelength > 420 nm) irradiation. The mechanism underlying the most enhanced photocatalytic activity of SnS 2 /CPVA-1%-180 °C-2 h was elucidated, based upon comparison between the optical, photoelectric and electrochemical impedance properties of SnS 2 nanocrystals and different SnS 2 /CPVA nanocomposites. Furthermore, the effects of photocatalytic experiment parameters (including dosage of photocatalyst, and initial pH and concentration of Cr(VI) aqueous solution) on the Cr(VI) removal efficiency by SnS 2 /CPVA-1%-180 °C-2 h were also studied. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) as a global epidemic disease is caused by Mycobacterium tuberculosis (M. tb). A small early secreted antigenic target 6-kDa protein (ESAT-6) secreted by M. tb has become a major virulence factor for detection of M. tb infection. Here, the recombinant protein His-CFP10-ESAT-6 (designated as rHis-CE) was expressed and purified as the immunogen to develop stable and specific ESAT-6 monoclonal antibodies (MAbs), which can recognize both recombinant and natural ESAT-6 protein. Three resultant ESAT-6 MAbs (named 4E1, 4D7 and 4G8) were characterized and screened in detail. An ultrasensitive electrochemical impedance ESAT-6 immunosensor for label-free detection of M. tb infection was proposed by the immobilization of the screening 4D7 ESAT-6 MAbs on the N-doped graphene oxide (N-GO) functionalized electrode. The structure and surface state of N-GO and ESAT-6 immunosensor were characterized by various characterization instruments such as transmission electron microscopy, X-ray photoelectron spectroscopy, contact angle measurement, and cyclic voltammetry. The quantitative detection of ESAT-6 was mainly achieved by recording the relative change of impedance before and after specificity reaction. Under the optimized conditions, ESAT-6 could be assayed in a range of 0.01–100 ng/mL with a very low detection limit of 7.0 pg/mL. Compared with the traditional assay methods, this immunosensor showed much higher sensitivity, wider linear range and simpler operation. Moreover, the ESAT-6 immunosensor showed good specificity, high reproducibility and excellent stability. A picogram level electrochemical impedance ESAT-6 immunosensor for label-free detection of M. tb infection was for the first time proposed by the immobilization of screening stable and specific 4D7 ESAT-6 monoclonal antibody on the N-doped graphene oxide functionalized electrode. [Display omitted] • Stable and specific ESAT-6 monoclonal antibodies (MAbs) were produced using His-CFP10-ESAT-6. • Screened 4D7 ESAT-6 MAbs were immobilized on the N-doped graphene (N-GO) functionalized electrode. • An ultrasensitive impedance ESAT-6 immunosensor for label-free detection of M. tb infection. • This immunosensor showed much higher sensitivity, wider linear range and simpler operation. [ABSTRACT FROM AUTHOR]

Polyaniline (PANI) was adopted to modify SnS 2 to develop a novel efficient visible-light-driven photocatalyst. SnS 2 /PANI composite was synthesized via first mixing of SnS 2 and PANI in N,N-Dimethylformamide solution and subsequent evaporation of N,N-Dimethylformamide. The characterization by Raman and Fourier transform infrared spectroscopy demonstrated the production of SnS 2 /PANI composite. UV–vis diffuse reflectance absorbance spectra showed that the coupling with PANI enhanced the visible-light-absorbing capability of SnS 2 . The photoluminescence and electrochemical impedance spectra showed that SnS 2 /PANI composite was more efficient in the separation and transfer of photogenerated charges than SnS 2 . The photocatalytic tests showed that SnS 2 /PANI composite exhibited notably higher photocatalytic activity than SnS 2 in reduction of aqueous Cr(VI) under visible-light (λ > 420 nm) irradiation (the rate of photocatalytic reduction of Cr(VI) by SnS 2 /PANI composite was nearly 4.2 times that by SnS 2 ). The possible reasons underlying the enhanced photocatalytic activity of SnS 2 /PANI composite were also proposed. [ABSTRACT FROM AUTHOR]

An effective and environmental-friendly method was adopted to enhance the Cr(VI) adsorption and photocatalytic reduction activity of g-C 3 N 4 , which was prepared by thermal condensation of melamine. The enhancement was realized by hydrothermal treatment of g-C 3 N 4 in 1.9–7.6 mol/L HNO 3 aqueous solutions at 80–120 °C for 3–12 h. The compositions, structures and physiochemical properties of the hydrothermally treated g-C 3 N 4 were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, N 2 adsorption/desorption isotherms, Zeta potential analysis, UV–vis diffuse reflectance spectroscopy and photocurrent measurement, and their dark adsorption and visible-light (wavelength >420 nm)-driven photocatalytic reduction of Cr(VI) in aqueous solution were tested. It was found that the hydrothermally treated g-C 3 N 4 exhibited significantly enhanced Cr(VI) adsorption and photocatalytic reduction activity than g-C 3 N 4 . Moreover, larger concentration of HNO 3 aqueous solution, higher hydrothermal temperature or longer treatment time resulted in higher Cr(VI) adsorption and photocatalytic reduction activity of the hydrothermally treated g-C 3 N 4 . The reasons accounting for the enhanced Cr(VI) adsorption and photocatalytic reduction activity of the hydrothermally treated g-C 3 N 4 were discussed, and the different mechanisms for the photocatalytic reduction of Cr(VI) over g-C 3 N 4 and the hydrothermally treated g-C 3 N 4 were also proposed. [ABSTRACT FROM AUTHOR]

This letter reports the preparation of visible light-driven N-modified Nb 2 O 5 photocatalyst by an alternative one-step solvothermal route, which employs nitric acid as the nitrogen source. N-modified Nb 2 O 5 nanoparticles (which were abbreviated as Nb 2 O 5 –HNO 3 ) were prepared directly through the solvothermal reactions of NbCl 5 , nitric acid (14.36–15.16 mol/L) and absolute ethanol at 200 °C for 15 h. The composition, structure and photoabsorption feature of Nb 2 O 5 –HNO 3 were characterized by X-ray photoelectron spectroscopy, transmission electron microscopy, N 2 adsorption/desorption isotherms and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of Nb 2 O 5 –HNO 3 was examined in the reduction of aqueous Cr(VI) under visible light ( λ >420 nm) irradiation, and compared with that of Nb 2 O 5 –NH 3 (which denoted the sample prepared when 13.32–14.44 mol/L ammonia water replaced nitric acid). It was observed that Nb 2 O 5 –HNO 3 displayed distinct absorption of visible light and high photocatalytic activity in the reduction of aqueous Cr(VI) under visible light ( λ >420 nm) irradiation, whereas Nb 2 O 5 –NH 3 exhibited no visible light-absorbing ability and no visible light-driven photocatalytic activity. This work suggests that nitric acid is an alternative nitrogen source for one-step solvothermal preparation of visible light-driven N-modified Nb 2 O 5 photocatalyst. [ABSTRACT FROM AUTHOR]

Partially conjugated polyvinyl chloride (CPVC)-modified TiO 2 nanoparticles were synthesized by heating the composite of polyvinyl chloride and TiO 2 nanoparticles in air at 150 °C for 1 h (the optimal heating duration among the investigated 0.5 h, 1 h, 2 h, 3 h and 4 h to obtain the most efficient CPVC/TiO 2 composite). The characterization results from X-ray diffraction, Raman spectra, X-ray photoelectron spectroscopy and high resolution transmission electron microscopy confirmed the formation of TiO 2 nanoparticles modified with CPVC. The UV–vis diffuse reflectance spectra indicated that the as-synthesized CPVC-modified TiO 2 nanoparticles had remarkable visible-light-absorbing ability. The photocatalytic experiments demonstrated that the as-synthesized CPVC-modified TiO 2 nanoparticles exhibited high photocatalytic activity in the reduction of aqueous Cr(VI) under visible-light ( λ >420 nm) irradiation, whereas sole CPVC and TiO 2 nanoparticles exhibited no photocatalytic activity in the reduction of aqueous Cr(VI) under visible-light ( λ >420 nm) irradiation. [ABSTRACT FROM AUTHOR]

An alternative simple, economical and efficient acid-soaking method was proposed to improve the activity of g-C 3 N 4 for photocatalytic reduction of aqueous Cr(VI) in this work. The improvement was achieved simply by soaking g-C 3 N 4 (which was obtained by heating melamine in air at 550 °C for 4 h) in 5 mol/L HNO 3 or HCl aqueous solution for 2 h (the HNO 3 and HCl-treated samples were denoted as g-C 3 N 4 HNO 3 and g-C 3 N 4 HCl, respectively). The compositions, structures, Brunner–Emmet–Teller (BET) specific surface areas, Zeta potentials and optical properties of g-C 3 N 4 , g-C 3 N 4 HNO 3 and g-C 3 N 4 HCl were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, N 2 adsorption/desorption isotherms, Zeta potential analyzer and UV–vis diffuse reflectance spectroscopy. The photocatalytic properties of g-C 3 N 4 , g-C 3 N 4 HNO 3 and g-C 3 N 4 HCl were tested in the reduction of aqueous Cr(VI) under visible-light ( λ > 420 nm) irradiation. It was observed that both g-C 3 N 4 HNO 3 and g-C 3 N 4 HCl exhibited higher photocatalytic activity than g-C 3 N 4 . The higher photocatalytic activities of acid-treated samples may be attributed to their larger BET specific surface areas, positive surface charges and larger adsorption capacities for Cr(VI). Furthermore, the soaking treatment with 5 mol/L HNO 3 aqueous solution can not only remove the Cr(III) species deposited on the surface of g-C 3 N 4 HNO 3 after use in photocatalytic reduction of aqueous Cr(VI), but also enhance the photocatalytic efficiency of g-C 3 N 4 HNO 3 in reuse. [ABSTRACT FROM AUTHOR]

This communication reports the development of a new efficient visible-light-driven composite photocatalyst comprising ZnFe 2 O 4 nanoparticles and conjugated polymer (CPVC) from the dehydrochlorination of polyvinyl chloride (PVC). ZnFe 2 O 4 /CPVC nanocomposites were synthesized via three main steps: (i) the synthesis of ZnFe 2 O 4 nanoparticles by a sol-gel method; (ii) the adsorption of PVC in tetrahydrofuran solution by ZnFe 2 O 4 nanoparticles to form ZnFe 2 O 4 /PVC nanocomposites; and (iii) the dehydrochlorination of PVC in the ZnFe 2 O 4 /PVC nanocomposites by heating at 150 °C for 2 h. X-ray diffraction, Fourier transform infrared spectroscopy and high-resolution transmission electron microscopy characterization revealed that the as-synthesized product was core/shell structured ZnFe 2 O 4 /CPVC nanocomposites. The photocatalytic results demonstrated that the ZnFe 2 O 4 /CPVC nanocomposites had much higher photocatalytic activity than ZnFe 2 O 4 nanoparticles in the reduction of aqueous Cr(VI) under visible-light (λ>420 nm) irradiation. Thus, ZnFe 2 O 4 /CPVC nanocomposites are promising for use as a new efficient visible-light-driven photocatalyst. [ABSTRACT FROM AUTHOR]

Abstract: A novel glucose biosensor was developed based on the direct electrochemistry of glucose oxidase (GOD) adsorbed in graphene/polyaniline/gold nanoparticles (AuNPs) nanocomposite modified glassy carbon electrode (GCE). Compared with graphene, polyanilline (PANI) or graphene/PANI, the graphene/PANI/AuNPs nanocomposite was more biocompatible and it offered a favorable microenvironment for facilitating the direct electron transfer between GOD and electrode. The adsorbed GOD displayed a pair of well-defined quasi-reversible redox peaks with a formal potential of −0.477V (vs. SCE) and an apparent electron transfer rate constant (k s ) of 4.8s−1 in 0.1M pH 7.0 PBS solution. The apparent Michaelis–Menten constant of the adsorbed GOD was 0.60mM, implying a fabulous catalytic activity and a remarkable affinity of the adsorbed GOD for glucose. The amperometric response of GOD-graphene/PANI/AuNPs modified electrode was linearly proportional to the concentration of glucose in the range of 4.0μM to 1.12mM with a low detection limit of 0.6μM at signal-to-noise of 3. The combination of the direct electron transfer character of GOD and the promising feature of graphene/PANI/AuNPs nanocomposite favors the selective and sensitive determination of glucose with improved analytical capabilities. [Copyright &y& Elsevier]

A novel glucose electrochemical biosensor was constructed based on the immobilization of glucose oxidase (GOx) in cage-like PbS nanostructure. The fabricated biosensor was characterized by scanning electron microscopy, UV–vis spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry, respectively. The direct electrochemistry of GOx at cage-like PbS nanostructure modified glassy carbon electrode was for the first time studied. The cage-like PbS nanostructure has larger surface area and provides a favorable microenvironment for facilitating the direct electron transfer between enzyme and electrode surface. The immobilized enzymes on PbS cage-like nanostructure retains its native structure and bioactivity and shows a surface controlled, reversible two-proton and two-electron transfer reaction with a apparent electron transfer rate constant of 2.85s−1. The biosensor shows wide linear range for glucose from 5.0×10−5 M to 1.45×10−3 M with high sensitivity of 11.02mAM−1 cm−2. The detection limit was calculated to be 1.0×10−5 M at signal-to-noise of 3. Moreover, the proposed glucose biosensor displays excellent selectivity, good reproducibility, and acceptable operational stability and can be successfully applied in the detection of glucose in serum sample. The cage-like PbS nanostructure provides a promising approach for immobilizing proteins and fabricating excellent biosensors. [ABSTRACT FROM AUTHOR]

Scheme 1. Illustration of preparation of HPG carbon/GCE and the mechanism for electrochemical oxidation of sunset yellow. [Display omitted] • We proposed a new ultrasensitive sunset yellow sensor by using 3D HPG carbon. • HPG carbon is featured with large surface area and a high content of sub-nanopores. • The sub-nanopores of HPG carbon improved the pre-concentration efficiency of SY. • The proposed sensor showed a wide linear range and ultra-low detection limit. • This research provided a universal platform for azo dye sensing applications. The content of sunset yellow (SY) in food must be strictly controlled, because its excessive intake may cause many adverse health effects. Herein, we proposed an ultrasensitive SY sensor by using hierarchical porous graphitic (HPG) carbon derived from polyaniline hydrogel. After a first step of polymerization, the HPG carbon was prepared through carbonization and further chemical activation. In particular, the activation process endowed the HPG carbon with a high content of optimized porous architecture (sub-nanoporous surface area accounts for more than 90% of microporous surface area), and thus providing a structural basis for high efficiency of SY pre-concentration on HPG carbon surface. Therefore, the proposed sensor showed record-high sensitivity (5285.7 A M−1 cm−2) and ultra-low detection limit (0.15 nM), which represents a performance improvement in SY sensing. Furthermore, the sensor displays excellent selectivity, reproducibility and stability, exhibiting a great perspective in ultrasensitive monitoring of SY in commercial products. [ABSTRACT FROM AUTHOR]

Abstract: A novel visible light sensitized photoelectrochemical sensing platform was constructed based on the perylene-3,4,9,10-tetracarboxylic acid/titanium dioxide (PTCA/TiO2) heterojunction as the photoelectric beacon. PTCA was synthesized via facile steps of hydrolysis and neutralization reaction, and then the PTCA/TiO2 heterojunction was easily prepared by coating PTCA on nano-TiO2 surface. The resulting photoelectric beacon was characterized by transmission electron microscope, scanning electron microscopy, X-ray diffractometry, FTIR spectroscopy, and ultraviolet and visible spectrophotometer. Using parathion-methyl as a model, after a simple hydrolyzation process, p-nitrophenol as the hydrolysate of parathion-methyl could be obtained, the fabricated derivative photoelectrochemical sensor showed good performances with a rapid response, instrument simple and portable, low detection limit (0.08nmolL−1) at a signal-to-noise ratio of 3, and good selectivity against other pesticides and possible interferences. It had been successfully applied to the detection of parathion-methyl in green vegetables and the results agreed well with that by GC–MS. This strategy not only extends the application of PTCA, but also presents a simple, economic and novel methodology for photoelectrochemical sensing. [Copyright &y& Elsevier]

Abstract: The dispersants used in oil spill disasters are claimed to be safe, but increased solubility of high-molecular-weight components in crude oil is of public health concern. The water-accommodated fractions (WAF) of crude oil mixed with dispersants may become airborne and cause lung epithelial damage when inhaled. This study was designed to examine the cell death and related death pathways of lung epithelial cells in response to WAF. Cultured A549 cells were treated for 2 or 24h with different concentrations of WAF. The WAF was prepared by mixing each of the dispersants (Corexit EC9527A, Corexit EC9500A and Corexit EC9580A) with crude oil for extraction with PBS. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay, lactate dehydrogenase assay, morphology and cleaved caspase 9 protein, and microtubule-associated protein 1 light chain 3 were all used to measure cell viability, necrosis, apoptosis and autophagy quantitation, respectively. Results showed that the WAF of oil-dispersant mixtures caused cell death in the lung epithelial cells, in a dose-dependent manner, with the major cellular pathways of necrosis and apoptosis involved. Autophagy also occurred in cells exposed to WAF mixtures at lower concentrations before any detectable cell death, indicating greater sensitivity to WAF exposure. The three types of cell behavior, namely necrosis, apoptosis and autophagy, may play different roles in oil spill-related respiratory disorders. [Copyright &y& Elsevier]

Abstract: This work reports a new method for the preparation and application of a kind of biocompatible calcium phosphate–gold nanoparticles (Ca3(PO4)2–AuNPs) nanocomposite. UV–vis spectroscopy and transmittance electron microscopy (TEM) have been used to monitor the formation process of the nanocomposite and to examine the interaction between calcium phosphate and gold nanoparticles (AuNPs). The nanocomposite has multiple sites and improved conductivity which make it suitable for the binding of proteins to construct electrochemical sensors. Myoglobin (Mb) adsorbed on the nanocomposite retained its native structure which was proved by Fourier transform infrared spectroscopy (FTIR). Direct electron transfer between the adsorbed Mb and the electrode was observed. Further results demonstrated that the adsorbed Mb has good electrocatalytic activity towards the reduction of H2O2 in the absence of any mediator. [Copyright &y& Elsevier]

Abstract: A ultrasensitive, simple and convenient electrochemical method was firstly developed for the determination of prochloraz and its metabolites as 2,4,6-trichlorophenol (2,4,6-TCP) using nano-aperture medical stone. Compared with the undoped disposable electrode (UDE), nano-aperture medical stone doped disposable electrode (MSDDE) not only significantly enhances the oxidation peak current of 2,4,6-TCP but also lowers the oxidation overpotential, suggesting that the nano-aperture MSDDE can remarkably improve the sensitivity of 2,4,6-TCP. The experimental conditions such as pH values of buffer solution, the content of nano-aperture medical stone, accumulation potential and time were optimized for the determination of 2,4,6-TCP. At optimal conditions, the oxidation peak current is proportional to the concentration of 2,4,6-TCP over the range from 6.0×10−9 to 8.0×10−5 molL−1. Finally, this novel method was successfully employed to detect prochloraz and its metabolites in orange rind with the detection limit of 8.4×10−10 molL−1 (0.3ngg−1) and the method was validated by gas chromatography. [ABSTRACT FROM AUTHOR]

A novel photoelectrochemical immunosensor was constructed to monitor carcinoembryonic antigen (CEA) based on hybridization chain reaction (HCR)-mediated in situ generation of copper nanoparticles (Cu NPs) and subsequent Cu2+-dependent quenching reaction, in which titanium dioxide nanoparticles-sensitized double-shell zinc cadmium sulfide hollow nanospheres (TiO 2 /DS-ZnCdS)-modified ITO electrode and anti-CEA antibody-modified 96-well plate served as biological recognition and signal detection platforms, respectively. The synergistic effect of TiO 2 NPs and DS-ZnCdS hollow nanospheres contributed to the improvement of photoelectric conversion efficiency, and HCR-mediated signal cascade benefited the enhancement of detection sensitivity. In the presence of CEA, biotin-labelled anti-CEA antibodies were immobilized onto anti-CEA antibody-modified 96-well plate, and triggered HCR process to form long double stranded DNA, which could adsorb a large number of Cu2+ ions and then in situ form Cu NPs on double stranded DNA template by a facile reduction reaction. After acid treatment, the dissolved Cu2+ ions could significantly reduce the photocurrent response due to the generation of Cu x S. Under optimal conditions, the immunosensor exhibited a desirable liner range of 1 pg mL−1 – 50 ng mL−1 and a low detection limit of 0.1 pg mL−1, as well as excellent selectivity and stability. Meanwhile, the recoveries of human serum sample analysis ranged from 96.8% to 103.6%, and the relative standard deviation was less than 7.40%, showing a good feasibility in early clinical diagnosis. • A novel photoelectrochemical immunosensor based on TiO 2 -sensitized DS-ZnCdS HNs was constructed for CEA detection. • HCR-mediated cascade process and Cu2+-based quenching reaction were integrated. • The photocurrent response was enhanced by TiO 2 /DS-ZnCdS heterostructure. • The excellent performances of designed immunosensor benefited to its potential application in early clinical diagnosis. [ABSTRACT FROM AUTHOR]

Abstract: A novel flow-through immunosensing system for chemiluminescent (CL) multianalyte immunoassay was designed based on channel-resolved technique. Using α-fetoprotein (AFP) and carcinoembryonic antigen (CEA) as model analytes, two polyethersulfone membranes modified with the corresponding capture antibodies were set in two channels of a flow cell, and then two mixtures of the sample and corresponding alkaline phosphatase labeled antibodies were introduced into the channels for on-line incubation, respectively. Upon injection of CL substrate the catalyzed CL signals from the two channels were sequentially collected with the aid of an optical shutter for CL detection of two analytes. The antibodies immobilized membranes could be regenerated for reuse. Under optimal conditions AFP and CEA could be assayed in the ranges of 5.0–150 and 0.50–80ng/ml with detection limits of 1.5 and 0.25ng/ml, respectively. The assay results of clinical serum samples with the proposed system were in acceptable agreement with those with the reference method in single-analyte test mode. This novel immunosensing system based on the designed channel-resolved technique provided an automated, reusable, simple, sensitive and low-cost approach for multianalyte immunoassay without using of expensive array detector. [Copyright &y& Elsevier]

Schematic diagram of the possible formation mechanism of hedgehog-like Bi2S3 micro-nanostructures. • A novel negative composite soft-template combining cationic surfactant CTAB and trimellitic acid is proposed. • The hedgehog-like bismuth sulfide micro-nanostructures can be controlled by hydrothermal method under the composite soft-template. • The possible formation mechanism of the hedgehog-like Bi 2 S 3 micro-nanostructures was explored. • The hedgehog-like Bi 2 S 3 sample could be employed to manufacture immune sensor. • The testing results indicated that the proposed-manner could be applied to detect serum AFP antigen. Taking a novel composite soft-template combining a cationic surfactant CTAB and trimellitic acid, the uniform hedgehog-like bismuth sulfide micro-nanostructures were successfully fabricated through a hydrothermal method, using Bi(NO 3) 3 as a bismuth source and thiourea as a sulfur source to slowly release S2− ions. The as-synthesized hedgehog-like bismuth sulfide micro-nanostructures, taking the outer diameter size of about 4 μm, were assembled by Bi 2 S 3 thin nanorods possessed nano-scale cross-section. The length of Bi 2 S 3 thin nanorods is up to 2 μm and the tip diameter size is around 50 nm, compared to the larger root diameter. XRD characterization of the as-prepared hedgehog-like bismuth sulfide nanomaterial testified its quadrature-phase crystal. The effects of the concentrations of reactants and additives on the morphology and size of Bi 2 S 3 particles were studied and the possible formation mechanism of the hedgehog-like Bi 2 S 3 micro-nanostructures was explored. The resulting hedgehog-like bismuth sulfide sample was employed to manufacture immune sensor and the testing result indicated that micro-nanostructures could not only enhance reaction current by employing the electrode reduction of hydrogen peroxide thionine by a HRP catalysis, but also the catalytic current intensity was linearly proportional to the AFP concentration in the range of 0.01∼20 ng/mL, with a linear correlation coefficient of 0.9974 and a slope of 0.2878. It is worth mentioning that the proposed-manner can be applied to detect serum AFP antigen. [ABSTRACT FROM AUTHOR]

• The high-temperature corrosion products have three layers structure. • There is a surge of sulfur content in the intermediate layer. • Coal quality and boiler combustion method determine the high temperature corrosion. The water wall of a 350 MW supercritical unit was severely corroded at high temperature in a short period. An analysis was made on the mechanism of high temperature corrosion of the water wall by chemical analysis, metallographic examinations, mechanical property test, and SEM observation. The results show that high temperature corrosion has no obvious effect on the material properties, and the main failure form is the reduction of tube wall by corrosion. Through the structure and composition analysis of corrosion products, it is found that there are three corrosion product layers on the outer wall of the water wall. Lots of holes existed between the corrosion product layer and the matrix, which made the corrosion product is easy to be spalled. The sulfur content in the corrosion product increases gradually from inside to outside, which proves that sulfur is the main factor affecting the high temperature corrosion of the water wall. [ABSTRACT FROM AUTHOR]

• Design and preparation of SnO 2 /SnS 2 /CPVC ternary composite as photocatalyst. • SnO 2 /SnS 2 /CPVC shows synergistically enhanced photoinduced charge separation. • SnO 2 /SnS 2 /CPVC has far higher visible-light photocatalytic activity. • SnO 2 /SnS 2 /CPVC shows good photocatalytic reusability and stability. • Useful for the development of new efficient ternary composite photocatalysts. A new high-efficiency ternary composite photocatalyst (SnO 2 /SnS 2 /conjugated polyvinyl chloride derivative (CPVC)) was designed based on the hypothesis that any two of its components can constitute type-II heterojunction, and its three components should have synergistic effect on the enhancement of photoinduced charge separation. SnO 2 /SnS 2 /CPVC ternary composite was prepared adopting an easy-to-implement four-step synthesis method. Photoluminescence and electrochemical impedance spectra showed that SnO 2 /SnS 2 /CPVC is more efficient than SnO 2 /SnS 2 , SnS 2 /CPVC, SnO 2 /CPVC and SnS 2 in the separation and transfer of photoinduced charges. Results from their photocatalytic reduction of Cr(VI) under visible-light irradiation indicated that SnO 2 /SnS 2 /CPVC has significantly higher visible-light photocatalytic activity than SnO 2 /SnS 2 , SnS 2 /CPVC, SnO 2 /CPVC, SnS 2 , CPVC and SnO 2. Moreover, SnO 2 /SnS 2 /CPVC also demonstrated good photocatalytic reusability and stability. This study not only has developed a new high-activity visible-light photocatalyst (SnO 2 /SnS 2 /CPVC), but is also useful for the design of other new ternary composite photocatalysts with synergistically enhanced visible-light photocatalysis. [ABSTRACT FROM AUTHOR]