Inhibition of Alzheimer's Aß1-42 Fibrillogenesis and Removal of Copper Ions by Polypeptides Modified Gold Nanoparticles.

Aggregation and fibrillation of ß-amyloid peptides (Aß) as well as accumulation of toxic metal ions have been believed to be the central events to cause Alzheimer's disease (AD). Thus, an attractive therapeutic tactic for AD is to design and synthesize inhibitors and metal chelators to prevent Aß aggregation and chelate toxic metal ions. In this study, the polypeptide functionalized gold nanoparticles (PFGNP) were obtained by modifying polypeptides Cys-Gly-Gly-Gly-Leu-Pro-Phe-Phe-Asp (CGGGLPFFD) and Cys-Gly-Gly-Gly-Gly-Gly-His (CGGGGGH) onto gold nanoparticles through gold-sulfur bond. The inhibitory properties of PFGNP toward Aß1-42 fibril formation was assessed by thioflavin T (ThT) fluorescence method and corroborated by atomic force microscopy analysis. The ability of PFGNP to complex copper ions was studied by electrochemical method. The experimental results reveal that PFGNP can effectively chelate copper ions and significantly inhibit the fibrillation of Aß1-42 . Moreover, PFGNP exhibits significantly protective effect on Aß-induced cytotoxicity toward human neuroblastoma SH-SY5Y cells.

Construction of AuNPs/reduced graphene nanoribbons co-modified molecularly imprinted electrochemical sensor for the detection of zearalenone.

In this work, a highly sensitive and selective molecularly imprinted electrochemical sensor is exploited to detect zearalenone (ZEA) by the synergistic effect of reduced graphene nanoribbons (rGNRs) and gold nanoparticles (AuNPs). The oxidized GNRs are firstly produced by an improved Hummers' oxidation method, and then reduced and modified together with AuNPs onto a glassy carbon electrode by electrodeposition technique to realize collaborative amplification of electrochemical signal. The molecularly imprinted polymer film with specific recognition sites can be generated on the modified electrode by electropolymerization. The effect of experimental conditions is systematically investigated to obtain the best detection performance. It is found that the constructed sensor shows a wide linear range of 1-500 ng·mL-1 for ZEA with a detection limit as low as 0.34 ng·mL-1. Obviously, our constructed molecularly imprinted electrochemical sensor shows great potential in the application of precisely detecting ZEA in food.