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[Display omitted] The development of the effective diagnostic method for the determination of cancer biomarkers is one of the most promising strategies for early clinical diagnosis of cancer. Here, based on the preparation of heterogeneous cuprous oxide coated silver (Ag@Cu 2 O) nanocomposites/graphitic carbon nitride (g-C 3 N 4)/cadmium sulfide (CdS) nanoarrays structure, a highly sensitive photoelectrochemical (PEC) biosensor for the examination of carcinoembryonic antigen (CEA) has been constructed successfully. The combination of photoactive semiconductor materials g-C 3 N 4 and CdS increases the electron transfer rate between them and enhances their photocurrent response, thus greatly increasing the concentration detection range. At the same time, the specific recognition between antigen and antibody is used to form a sandwich structure secondary antibody (Ab 2)/CEA/antibody (Ab 1). And because Ag@Cu 2 O has the function of absorbing light and consuming electron donor. Therefore, the successful measurement of CEA was achieved by labeling Ag@Cu 2 O on Ab 2 and finally immobilizing it on the sensor to correlate the current reduction with the CEA concentration. The sandwich PEC biosensor proposed by this signal amplification strategy under optimal conditions has good analytical performance for CEA, with a wide linear detection range (from 10-5 to 1 ng/mL) and a low detection limit of 0.0011 pg/mL. The PEC biosensor constructed by this method showed high sensitivity, excellent anti-interference ability, favourable repeatability, and good stability. [ABSTRACT FROM AUTHOR]

Nanostructure Mn 3 O 4 is a promising pseudocapacitive electrode material due to its low cost, environmental compatibility, and intrinsically high capacity. However, the poor electrical conductivity and low accessible active sites limit its performance. We report that one-dimensional (1D) nanoscale Mn 3 O 4 has been coupled with reduced graphene oxide (RGO) to fabricate RGO/Mn 3 O 4 nanohybrid (MORGO) as a pseudocapacitive electrode material with high capacitance. The selective reduction of graphene oxide (GO) in Mn 3 O 4 /graphene oxide (MOGO) to reduced graphene oxide (RGO) while sustaining the unchanged oxidation state of manganese is the key to obtain MORGO. Specific surface area of MORGO is 14 times higher than pure Mn 3 O 4 , and the charge transfer resistance decreases 3.2 times. These enhanced properties lead to excellent specific capacitance of 538 F g −1 at the current density of 0.1 A g −1 , and of 472 F g −1 at 10 A g −1 in 1 M Na 2 SO 4 aqueous electrolyte. The capacitance retained 89% after 2000 cycles, demonstrating its excellent long-term cycling stability. [ABSTRACT FROM AUTHOR]

Abstract: Some research has reported interaction between polyamidoamine dendrimers or polyethylenimine and quantum dots causing a quantum yield decrease of quantum dots. In this work, however, polyethylenimines of different molecular weight that were used to modify CdS quantum dots gave rise to the enhancement of CdS quantum yield to nearly 100%. Herein, we present the synthesis of a kind of easily prepared high-quantum-yield CdS quantum dot in aqueous solution and the study of the interaction between CdS and polyethylenimine. [Copyright &y& Elsevier]

[Display omitted] Metal-organic polymers (MOPs) can enhance the photoelectrochemical (PEC) water oxidation performance of BiVO 4 photoanodes, but their PEC mechanisms have yet to be comprehended. In this work, we constructed an active and stable composite photoelectrode by overlaying a uniform MOP on the BiVO 4 surface using Fe2+ as the metal ions and 2,5-dihydroxyterephthalic acid (DHTA) as ligand. Such modification on the BiVO 4 surface yielded a core-shell structure that could effectively enhance the PEC water oxidation activity of the BiVO 4 photoanode. Our intensity-modulated photocurrent spectroscopy analysis revealed that the MOP overlayer could concurrently reduce the surface charge recombination rate constant (k sr) and enhance the charge transfer rate constant (k tr), thus accelerating water oxidation activity. These phenomena can be ascribed to the passivation of the surface that inhibits the recombination of the charge carrier and the MOP catalytic layer that improves the hole transfer. Our rate law analysis also demonstrated that the MOP coverage shifted the reaction order of the BiVO 4 photoanode from the third-order to the first-order, resulting in a more favorable rate-determining step where only one hole accumulation is required to overcome water oxidation. This work provides new insights into the reaction mechanism of MOP-modified semiconductor photoanodes. [ABSTRACT FROM AUTHOR]