Nanozyme-mediated cascade reaction system for electrochemical detection of 1,5-anhydroglucitol.

Diabetes is one of metabolic diseases affecting major human health. The early diagnosis and treatment of diabetes have significant benefits. 1,5-anhydroglucitol (1,5-AG) accurately reflects a patient's average blood glucose level for the past 3-7 days and becomes a promising marker for real-time detection of diabetes. In this study, a novel biosensor for determination 1,5-AG is constructed using reduce graphene oxide-carboxymethylated chitosan-hemin@platinum nanocomposites (rGO-CMC-H@Pt NCs) nanozyme and pyranose oxidase (PROD) enzyme as the electrochemical biosensing platform. The rGO-CMC-H@Pt NCs nanozyme has good electro-conductibility, high specific surface area, and admirable peroxide-like catalysis effect to enhance the electrochemical response. 1,5-AG is catalyzed by PROD and produces hydrogen peroxide (H2O2), which in turn can be decomposed by rGO-CMC-H@Pt NCs and produce a current signal recorded by differential pulse voltammetry (DPV) technique. Under optimal conditions, the response currents have a linear relationship in the 1,5-AG concentration of 0.1-2.0 mg/mL with R2 of 0.9869. The sensitivity is 2.1895 µA/µg·mL-1 and the limit of detection (LOD) is 38.2 µg/mL (S/N = 3). In addition, the specificity, reproducibility, stability and recovery (94.5-107.6%) of 1,5-AG biosensors all exhibit good performance. Therefore, the designed 1,5-AG biosensor has a good effect and can be used for the diagnosis of diabetes.

One-step oxidation preparation of unfolded and good soluble graphene nanoribbons by longitudinal unzipping of carbon nanotubes.

A simple one-step method to prepare graphene nanoribbon (GNR) is reported in this paper. Compared with water steam etching, the oxidation and co-etching of dilute sulfuric acid can result in the more complete longitudinal unzipping of carbon nanotube, although there is no other strong oxidant. As-prepared GNRs are more flat and have more oxygenated functional groups along the edge. Moreover, they can steadily disperse in a water system. These make them suitable as a carrier for supporting palladium (Pd) nanoparticles. The Pd/GNR composite exhibits a superior electrocatalytic activity for ethanol oxidation.