基于DNA/Nafion-聚二烯丙基二甲基氯化铵功能化的石墨烯电化学传感器评价阿魏酸及当归水提物抗氧化活性

Electrochemical Sensor for Assessment of Antioxidant Activities of Ferulic Acid and Extract in Angelica Sinensis Based on DNA/NafionPoly(diallyldimethylammonium chloride) Functionalized Graphene

构建了DNA/Nafion-聚二烯丙基二甲基氯化铵功能化的石墨烯修饰的玻碳电极(DNA/NA-PDDA-G/GCE),用于DNA氧化损伤的监测及阿魏酸和当归水提物抗氧化活性的评价。采用循环伏安法(CV)和交流阻抗法(EIS)对NA-PDDA-G和DNA修饰后的玻碳电极进行电化学表征,并采用扫描电子显微镜(SEM)对修饰电极表面形貌进行表征。以Ru(NH_3)_6^(3+)为探针,采用方波伏安法(SWV)筛选出DNA/NA-PDDA-G/GCE电化学传感器在p H 7.0,Fe^(2+)和H_2O_2的配比为1∶5的Fenton体系中,经·OH诱导损伤30 min后DNA的损伤程度最大。实验结果表明,当归水提物的抗氧化活性强于阿魏酸单体,但总体来说两者的抗氧化活性都弱于L-抗坏血酸。本方法具有简单、成本低、灵敏度高、重现性好等优点,可用于DNA损伤的监测,以及于抗氧化剂活性大小的评价。

A simple electrochemical sensor was constituted based on the glassy carbon electrode（ GCE）surface modified with nafion-poly（ diallyldimethylammonium chloride） functionalized graphene sheets（ NAPDDA-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（ NH_3）_6^（3＋） was used as an electroactive indicator to monitor DNA damage induced by hydroxyl radical（ · 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 Fe SO_4 and 5. 0 mmol / L H_2O_2 at p H 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.