关键词: 谷胱苷肽, 功能化纳米金, 二茂铁, 巯基识别

Abstract: An electrochemical detection method for the cross-linking reaction and sulfhydryl-specific identification of GSH using ferrocene-capped gold nanoparticles/streptavidin conjugates was developed in this paper. Disulfide C11-NHS organic molecules were covalently immobilized on a gold electrode via {Au-S} bonds(-S-S-is reduced to-SH easily in ethyl acetate solution) and formed compact self-assembled monolayers(SAMs). Then GSH is attached to C11-NHS through the amide formation and continues to cross-link Biotin-maleimide by forming a stable thioether bond between the sulfhydryl group and double bond of the maleimide group. Finally, the ferrocene-capped functional gold nanoparticles were introduced via strong interaction effect between biotin and streptavidin. The binding events were monitored by electrochemical signal of ferrocene covering on the gold nanoparticles by voltammetry. The signal differences permit to distinguish whether there is free sulfhydryl groups in the surface-bound biomolecules. The ferrocene signal is enlarged greatly because of quantities of ferrocene moieties covering on the nanogold surface. The well-defined redox peaks attribute to that of ferrocene immobilized through the cross-linking reaction between sulfhydryl groups in GSH and maleimide groups in Biotin-maleimide. The sensitivity of this electrochemical biosensor was detected and an excellent linearity of 5 μmol/L-0.1 mmol/L for GSH concentration with the oxidation current and a detection limit of 1 mmol/L were also achieved.

Key words: Glutathione, Functional gold nanoparticles, Ferrocene, Sulfhydryl-specific identification