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In this work, an ultrasensitive electrochemical immunosensor was developed for detecting carcinoembryonic antigen (CEA) based on Ag/MoS 2 @Fe 3 O 4 and an analogous enzyme linked immunosorbent assay (ELISA) method. The fabrication process was conducted by using 96-well microplate and the detection process was executed on magnetic glassy carbon electrode (MGCE), which was named analogous ELISA method. The technique of total internal reflection fluorescence (TIRF) was firstly employed to verify the feasibility of the proposed method. A sandwich-type strategy was applied for the fabrication of the immunosensor and Ag/MoS 2 @Fe 3 O 4 was used as label. Simultaneously, Ag nanoparticles (Ag NPs) were applied for modifying the MGCE as sensing platform due to its excellent electroconductivity. Ag/MoS 2 @Fe 3 O 4 could firmly attached on the surface of MGCE thanks to the magnetic property of Fe 3 O 4 . Differential pulse voltammetry (DPV) was applied for the detection of CEA and electrochemical impedance spectroscopy (EIS) confirmed the successful fabrication of the immunosensor. Under optimal experimental conditions, a linear response was achieved in the range of 0.0001–20 ng/mL with a low detection limit of 0.03 pg/mL. Furthermore, the proposed immunosensor exhibited good stability, excellent selectivity and fine reproducibility. This proposed strategy provides a new thought and a potential approach for clinical diagnosis of other tumor markers. [ABSTRACT FROM AUTHOR]

In this work, a label-free electrochemical immunosensor was developed for the quantitative detection of carcinoembryonic antigen (CEA). Flower-like Ag/MoS 2 /rGO nanocomposites were employed as the signal amplification platform of the designed immunosensor for the first time. Due to the synergistic effect between molybdenum disulfide (MoS 2 ), reduced graphene oxide (rGO) and Ag nanoparticles (NPs), Ag/MoS 2 /rGO nanocomposites could provide a high sensitivity for the label-free electrochemical immunosensor. The detection mechanism was based on the monitoring of the electrocatalytic current response change towards the reduction of hydrogen peroxide (H 2 O 2 ) when immunoreaction occurred on the surface of the electrode modified with Ag/MoS 2 /rGO nanocomposites. Using amperometric i-t curve to record the electrocatalytic process, the proposed immunosensor achieved an ultrasensitive and specific detection of CEA with a low detection limit of 1.6 fg/mL. Under optimal conditions, the fabricated immunosensor exhibited acceptable reproducibility, selectivity and excellent stability. This designed immunosensor could provide an effective method in the clinical diagnosis of other tumor markers. [ABSTRACT FROM AUTHOR]

In this work, silver nanoparticles functionalized cuprous oxide nanowires (Ag@Cu 2 O) nanocomposites were synthesized by a simple method. The nanostructure of it could be well confirmed by a scanning electron microscope (SEM) image. Due to the good synergistic effect between silver nanoparticles (Ag NPs) and cuprous oxide nanowires (Cu 2 O NWs), Ag@Cu 2 O nanocomposites displayed a good electrocatalytic performance towards the reduction of hydrogen peroxide (H 2 O 2 ). Cyclic voltammograms (CVs) were employed to investigate electrocatalytic mechanism of it. Using Ag@Cu 2 O nanocomposites as the labels, a novel and ultrasensitive sandwich-type electrochemical immunosensor was developed for the quantitative detection of carcinoembryonic antigen (CEA). Due to the special electrochemical performance of Ag@Cu 2 O nanocomposites, the facile and sensitive fabrication of the designed immunosensor was achieved. Under optimal conditions, the designed immunosensor exhibited a wide linear range with a low detection limit. It also displayed an electrochemical performance with good reproducibility, selectivity and stability, which would provide potential applications in the clinical diagnosis of other tumor markers. [ABSTRACT FROM AUTHOR]

Abstract: A new phthalocyanine material, 2,9,16,23-tetrakis [4-(hexafluoroisopropanol)-anilinomethyl]phthalocyaninato zinc (ZnPcF24N4O4) was designed and synthesized. The chemoselective material was coated on a 300MHz surface acoustic wave (SAW) device using cyclic voltammetry for the detection of sarin (GB) vapor. It was found that the observed frequency shifts were linear to the concentrations of sarin in the range of 0.6–43.4mg/m3 with a high sensitivity of 205.8Hz/mg/m3. The influences of other interfering vapors on the sensor response were also examined. The results showed that the phthalocyanine-based SAW sensor exhibited a fairly fast response, excellent reversibility, linearly sensitivity, and a high selectivity to vapor of the organophosphorus nerve agent GB. [Copyright &y& Elsevier]