Homogeneous Fluorescence Resonance Energy Transfer Immunoassay for the Determination of Zearalenone

<div><p>This study demonstrates the use of antigen-antibody binding for the detection of zearalenone. Based on the principle of the fluorescence resonance energy transfer (FRET) phenomenon between antibody and antigen, an immunoassay, in which zearalenone coupled with the anti-zearalenone antibody, was developed, optimized, and applied. Owing to intrinsic fluorescence properties in basic pH conditions with the optimal cationic surfactant, anti-zearalenone and zearalenone played roles as the respective donor and acceptor in the FRET immunoassay. As the concentration of analyte increased, the antigen/antibody emission intensity ratio (<i>I</i>_430 nm/<i>I</i>_350 nm) was enhanced due to larger amounts of zearalenone/anti-zearalenone complexes. This assay, based on the ratio of intensities (<i>I</i>_430 nm/<i>I</i>_350 nm), displayed high specificity and sensitivity with a detection limit of 0.8 ng mL⁻¹ for zearalenone. The results obtained from analysis of spiked wheat grain samples were found to be in good agreement with those obtained by employing a direct competitive enzyme-linked immunosorbent assay. The label-free, noncompetitive, and homogeneous FRET immunoassay strategy served as a powerful tool for the simple, rapid, and sensitive quantitative determination of zearalenone in food and feed matrices.</p> </div

Structurally Nanocrystalline-Electrically Single Crystalline ZnO-Reduced Graphene Oxide Composites

ZnO, a wide bandgap semiconductor, has attracted much attention due to its multifunctionality, such as transparent conducting oxide, light-emitting diode, photocatalyst, and so on. To improve its performances in the versatile applications, numerous hybrid strategies of ZnO with graphene have been attempted, and various synergistic effects have been achieved in the ZnO–graphene hybrid nanostructures. Here we report extraordinary charge transport behavior in Al-doped ZnO (AZO)-reduced graphene oxide (RGO) nanocomposites. Although the most challenging issue in semiconductor nanocomposites is their low mobilities, the AZO–RGO nanocomposites exhibit single crystal-like Hall mobility despite the large quantity of nanograin boundaries, which hinder the electron transport by the scattering with trapped charges. Because of the significantly weakened grain boundary barrier and the proper band alignment between the AZO and RGO, freely conducting electrons across the nanograin boundaries can be realized in the nanocomposites. This discovery of the structurally nanocrystalline-electrically single crystalline composite demonstrates a new route for enhancing the electrical properties in nanocomposites based on the hybrid strategy