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An efficient quenching electrochemiluminescence (ECL) immunosensor based on ECL resonance energy transfer (ECL-RET) was studied for sensitive analysis of prostate specific antigen (PSA). In this protocol, nitrogen-doped graphene quantum dots (NGQDs) which could produce excellent ECL emission, were loaded onto Ni(OH) 2 with the three-dimensional (3D) hierarchical and stacked lamellar structure. Taking advantages of high conductivity and large specific surface area of Ni(OH) 2 , the better electrochemical and ECL behavior of Ni(OH) 2 /NGQDs were presented. As another part of immunosensor, the Fe 3 O 4 @MnO 2 composites with wider ultraviolet absorption range were successfully assembled. The absorption spectra of Fe 3 O 4 @MnO 2 precisely overlapped with the ECL spectra of NGQDs, leading to the significant decrement of ECL signal. Herein, the sandwich-type immunosensor was developed based on the quenching mechanism between NGQDs (ECL donor) and Fe 3 O 4 @MnO 2 (ECL acceptor). The system was optimized to realize reliable determination of PSA concentration within the linear range of 10 −5 –10 ng/mL and a detection limit of 5 fg/mL (S/N = 3). Eminently, the developed method was successfully applied in real serum samples with good recoveries in a range from 94.0% to 102%, indicating the good accuracy of the proposed method for PSA detection. [ABSTRACT FROM AUTHOR]

An ultrasensitive sandwich-type electrochemical immunosensor was designed for the quantitative detection of alpha fetoprotein (AFP). The β-cyclodextrins functionalized graphene sheets (CD-GS) were used as the sensing matrix for immobilizing adamantine-1-carboxylic acid functionalized primary anti-AFP (ADA–Ab 1 ) and enhanced the electron transfer. PdNi alloy nanoparticles decorated N-doped graphene nanoribbons (PdNi/N-GNRs) were used as labels of secondary anti-AFP (Ab 2 ), and PdNi alloy nanoparticles (PdNi NPs) exhibited high catalytic performance towards the reduction of H 2 O 2 . Meanwhile, with good dispersion, large specific surface area and good catalytic performance, N-doped graphene nanoribbons (N-GNRs) significantly amplified the electrochemical signal. Under the optimal conditions, the electrochemical immunosensor exhibited a wide linear range of 0.0001–16 ng/mL with a low detection limit of 0.03 pg/mL. Additionally, the proposed immunosensor showed high specificity, good reproducibility and long-term stability, which have promising application in bioassay analysis. [ABSTRACT FROM AUTHOR]

Electrochemical corrosion behavior of platinum coated (Pt-coated) lanthanum doped titanium-zirconium-molybdenum alloy (La-TZM alloy) was studied in this paper. La-TZM alloy plates were fabricated using powder metallurgy and rolling technique, and platinum was coated on their surfaces by using electroplating. Corrosion behavior of Pt-coated La-TZM alloy samples were investigated in neutral and alkaline medium while the Cl − concentrations keep invariant, which was quantitatively analyzed using potentiodynamic polarization, scanning electron microscope and energy spectrum techniques. Results show that the Pt-coating can improve the corrosion resistance of the La-TZM alloy. Pt-coating on La-TZM alloy can effectively hinder the matrix alloy electrochemical corrosion during different corrosion mediums. In addition, the Pt-coating on La-TZM alloy in a neutral medium is more corrosion resistant than that in an alkaline medium. Pt-coating can effectively hinder the Cl − destroys the corrosion formed on the surface passivation film, OH − and Cl − double erosion promoted La-TZM alloy intergranular corrosion increased during the electrochemical corrosion processes. [ABSTRACT FROM AUTHOR]

Abstract: Constructions of versatile electroactive labels are key issues in the development of electrochemical immunosensors. In this study, copper-doped titanium dioxide nanoparticle (Cu@TiO2) was synthesized and used as labels for fabrication of sandwich-type electrochemical immunosensors on glassy carbon electrode (GCE). Due to the presence of copper ions, Cu@TiO2 shows a strong response current when coupled to an electrode. The prepared nanocomposite also shows high electrocatalytic activity towards reduction of hydrogen peroxide (H2O2). The dual functionality of Cu@TiO2 enables the fabrication of immunosensor using different detection modes, that is, square wave voltammetry (SWV) or chronoamperometry (CA). While Cu@TiO2 was used as labels of secondary antibodies (Ab2), carboxyl functionalized graphene oxide (CFGO) was used as electrode materials to immobilize primary antibodies (Ab1). Using human immunoglobulin G (IgG) as a model analyte, the immunosensor shows high sensitivity, acceptable stability and good reproducibility for both detection modes. Under optimal conditions, a linear range from 0.1pg/mL to 100ng/mL with a detection limit of 0.052pg/mL was obtained for SWV analysis. For CA analysis, a wider linear range from 0.01pg/mL to 100ng/mL and a lower detection limit of 0.0043pg/mL were obtained. The proposed metal ion-based enzyme-free and noble metal-free immunosensor may have promising applications in clinical diagnoses and many other fields. [Copyright &y& Elsevier]

Currently, the quality of hole transport layers (HTLs) plays a vital role in achieving the high-efficiency perovskite solar cells (PSCs). The 2,2′,7,7′-tetrakis-(N, N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene (Spiro-OMeTAD) based HTLs usually suffer from pinholes and defects which would cause the performance degradation. Here, a series of polyoxometalate (POM) crystals with mixing different transition metal ions, named Na 10 [M 2 (solvent) 6 (WO 2) 2 (BiW 9 O 33) 2 ] (BiW 10 M, M = Mn, Co), are synthesized and used as dopants to improve the properties of Spiro-OMeTAD based HTLs. We observe that the effects of oxidation abilities for Spiro-OMeTAD could be tuned by mixing transition metal ions. Besides, the morphologies of HTLs are significantly improved and the power conversion efficiencies (PCEs) of BiW 10 M doped PSCs are enhanced from 18.48% (control device) to 20.31% (BiW 10 Mn) and 20.12% (BiW 10 Co), respectively. Moreover, doping transition metal ions can also prevent the water penetration, thus the device stability of BiW 10 M doped PSCs is also obviously enhanced. In this work, metal ions doped POMs are proved to be low-cost and facile chemical additives for oxidizing Spiro-OMeTAD, which provide an efficient strategy to fabricate high-performance and stable PSC devices. [Display omitted] • The BiW 10 M promotes the generation of Spiro-OMeTAD+. • The optimal PCE of 20.31% of BiW 10 Mn doped PSCs has been achieved. • The high PCEs benefit from the efficient charge collection. • The pinhole-free doped HTL films based on BiW 10 M has been prepared. • The BiW 10 M enhances the repeatability and stability of devices. [ABSTRACT FROM AUTHOR]