Molecular identification and putative role of insulin growth factor binding protein-related protein (IGFBP-rp) in the swimming crab Portunus trituberculatus.

The insulin-like growth factor/insulin-like polypeptide (IGF/ILP) signaling is vital for growth, physiological metabolism, development, and reproduction. Insulin-like growth factor-binding protein (IGFBP) is involved in the insulin signaling pathway in both vertebrates and invertebrates and is critical for various physiology functions. Herein, we cloned and characterized the full-length cDNA of IGFBP-rp in the swimming crab, Portunus trituberculatus (PtIGFBP-rp). The deduced amino acid sequence of PtIGFBP-rp was found to contain three key domains (insulin-like binding (IB) domain, the kazale-type serine protease inhibitor (KAZAL) domain, and the immunoglobulin-like C2 (IGc2) domain). Results showed that PtIGFBP-rp shared the same expression pattern as P. trituberculatus insulin androgenic gland hormone (PtIAG) transcripts during the embryonic larval, juvenile crab stage and the androgenic gland (AG) developmental cycle. Moreover, PtIGFBP-rp transcripts were also present in high abundance in hepatopancreas, muscle, and androgenic glands. The regulatory relationship between PtIGFBP-rp and PtIAG was investigated by RNA interference and co-localization assays, which showed a co-localization relationship and feedback regulation between them. Bilateral eye stalk ablation (ESA) increased the expression of PtIGFBP-rp in the AG at 7 d after surgery. These results demonstrate the involvement of PtIGFBP-rp in the signaling regulatory network of IAG in P. trituberculatus.

Non-enzymatic glucose sensors based on controllable nanoporous gold/copper oxide nanohybrids.

A kind of dealloyed nanoporous gold (NPG)/ultrathin CuO film nanohybrid for non-enzymatic glucose sensing has been prepared by a simple, in-situ, time-saving and controllable two-step electrodeposition. The three-dimensional and bicontinuous nanoporous structure of the nanocomposites have been characterized by scanning electron microscope (SEM) and transmission electron microscopy (TEM), and the electrochemical tests have been estimated by cyclic voltammetry and single potential step chronoamperometry (SPSC). The optimal NPG/CuO electrode exhibits great electrocatalytic activity towards glucose oxidation and also shows obvious linear response to glucose up to 12 mM with a high sensitivity of 374.0 µA cm(-2)mM(-1) and a good detection limit of 2.8 µM (S/N=3), as well as strong tolerance against chloride poisoning and interference of ascorbic acid and uric acid.

Examining the effects of self-assembled monolayers on nanoporous gold based amperometric glucose biosensors.

Nanoporous gold (NPG) based biosensors have been constructed by covalently immobilizing glucose oxidase (GOx) onto self-assembled monolayers (SAMs). With p-benzoquinone (BQ) as a mediator, diffusion behavior and amperometric biosensor performance are evaluated by electrochemical characterization. The enzyme modified electrodes are demonstrated to show a thickness-sensitive behavior. Compared with planar polycrystalline gold, the unique porous structure of NPG has also been characterized via an electrochemical surface reconstruction process. Single-crystal gold-like electrochemical behavior on NPG and a comprehensive understanding of its impacts on sensor performance have been proposed.

One-step fabrication of bio-functionalized nanoporous gold/poly(3,4-ethylenedioxythiophene) hybrid electrodes for amperometric glucose sensing.

We report a simple, one-step synthesis of hybrid film by electropolymerizing 3,4-ethylenedioxythiophene (EDOT) on nanoporous gold (NPG) for applications in amperometric glucose biosensors. The enzyme, glucose oxidase (GOx), is entrapped into poly(3,4-ethylenedioxythiophene) (PEDOT) matrix, simultaneously. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) studies show the NPG preserve its original bicontinuous nanoporous structure and the PEDOT film grows uniformly with a thickness of ~10 nm. The modified electrodes have been investigated by cyclic voltammetry (CV) and single potential step chronoamperometry (SPSC). The influence of PEDOT film's thickness has been explored to optimize sensor behaviors. Mediated by p-benzoquinone (BQ), the calibration curves have been obtained by applying relatively low constant potential of 200 mV (vs. SCE). The NPG/PEDOT/GOx (2CVs) biosensor exhibits high sensitivity of 7.3 µA mM(-1) cm(-2) and a wide linear range of 0.1-15 mM, making it suitable for reliable analytic applications.