Sensitive detection of ketamine with an electrochemical sensor based on UV-induced polymerized molecularly imprinted membranes at graphene and MOFs modified electrode.

Ketamine is one of the most widely abused drugs in the world and poses a serious threat to human health and social stability; therefore, the ability to accurately monitor the substance in real-time is necessary. However, several problems still exists towards this goal, such as the generally low concentration of the target molecules disturbed in the complex samples that undergo analysis during criminal investigations. In this work, the sensitive and selective detection of ketamine was accomplished by molecularly imprinted electrochemical sensor. The molecularly imprinted membrane as a biomimetic recognition element was fabricated by the UV-induced polymerization of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) on a metal-organic framework/graphene nanocomposite (MOFs@G) modified screen-printed electrode. The screen printed electrode (SPE) provided good adhesion for the formation of the imprinted membranes and increased the stability of the sensor. The morphology and performance of the imprinted films were characterized in detail by scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The experimental results demonstrated that the imprinted sensor had excellent sensitivity, selectivity, and long-term stability. It offered a low detection limit (4.0 × 10-11 mol L-1) and had a dynamic range from 1.0 × 10-10 mol L-1 to 4.0 × 10-5 mol L-1. Furthermore, the established method was successfully applied for the determination of ketamine in urine and saliva samples.

ZmGRF, a GA regulatory factor from maize, promotes flowering and plant growth in Arabidopsis.

Transcription factors that act as positive regulators of gibberellin (GA) biosynthetic genes in plants are not well understood. A nuclear-localized basic leucine zipper transcription factor, ZmGRF, was isolated from maize. The core DNA sequence motif recognized for binding by ZmGRF was CCANNTGGC. ZmGRF overexpression in transgenic Arabidopsis plants promoted flowering, stem elongation, and cell expansion. Chromatin immunoprecipitation assays revealed that ZmGRF bound directly to the cis-element CCANNTGGC in the promoter of the Arabidopsis ent-kaurene oxidase (AtKO1) gene and promoted AtKO1 expression. GA4 content increased by 372-567% in transgenic Arabidopsis plants overexpressing ZmGRF compared to wild-type control plants. The GIBBERELLIN-INSENSITIVE DWARF1 gene, which encodes a GA receptor, was also upregulated and the growth-repressing DELLA protein gene GA INSENSITIVE was downregulated. Our results showed ZmGRF functioned through the GA-signaling pathway.