▎ 摘　　要

A simple electrochemical sensor was constituted based on the glassy carbon electrode (GCE) surface modified with nafion-poly (diallyldimethylammonium chloride) functionalized graphene sheets (NA-PDDA-G) composite film and herring sperm double. stranded DNA for direct detection of DNA damage in vitro and evaluation of the antioxidant properties of ferulic acid (FA) and the aqueous extracts in Angelica Sinensis (EAS). Scanning electron microscopy (SEM) was used to characterize the morphologies of the fabricated sensor, while cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the electrochemical performances of the modified electrode. Ru(NH3)(6)(3+) was used as an electroactive indicator to monitor DNA damage induced by hydroxyl radical (center dot OH) with square wave voltammetry (SWV). The fabricated sensor showed the greatest degree of DNA oxidation damage occurred under the conditions of 30-min incubation in Fenton reagent containing 1.0 mmol/L FeSO4 and 5.0 mmol/L H2O2 at pH 7.0. The antioxidant activity of extract in Angelica Sinensis (EAS) was stronger than that of FA, while they were all weaker than that of ascorbic acid (AA). The proposed sensor not only exhibited excellent stability and reproducibility, but would be a simple and novel method for assessment of antioxidant properties of medicinal herb components.