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本文利用巯基化单链DNA(ssDNA)自组装修饰在金电极表面,制备了ssDNA修饰金电极(ssDNA/Au);在最优化条件下,与互补片段杂交制备了相应的双链DNA修饰金电极(dsDNA/Au),构建了一种快速、简便、价廉的检测黄曲霉毒素B1(AFB1)的新型电化学DNA生物传感器。采用循环伏安法(CV)和示差脉冲伏安法(DPV)等电化学方法表征了电子媒介体铁氰化钾和亚甲基蓝(MB)在ssDNA/Au和dsDNA/Au界面上的电化学行为。一定浓度的黄曲霉毒素B1(AFB1)诱导dsDNA/Au造成DNA损伤,使得MB电化学信号降低,实现了快速检测AFB1。在最优化条件(在4℃下,ssDNA在金电极上自组装14 h,与cDNA在37℃下杂交2 h,制备了dsDNA/Au电极;37℃下,AFB1溶液诱导损伤DNA 22 min后),该方法对AFB1的线性检测范围为10~500 ng/mL,加标回收率在95.99%~104.57%。建立的AFB1诱导DNA损伤方法可以实现对AFB1快速、简便、准确的定量检测。
In this paper, ssDNA modified gold electrode (ssDNA / Au) was prepared by self-assembly of thiolated single-stranded DNA (ssDNA) on the surface of gold electrode. Under optimal conditions, the hybridization of the double- (dsDNA / Au), a novel electrochemical DNA biosensor for the detection of aflatoxin B1 (AFB1) was constructed, which was rapid, simple and inexpensive. The electrochemical behavior of electron mediator potassium ferricyanide and methylene blue (MB) at ssDNA / Au and dsDNA / Au interface was characterized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). A certain concentration of aflatoxin B1 (AFB1) induces DNA damage by dsDNA / Au, resulting in a decrease in MB electrochemical signal, enabling rapid detection of AFB1. The dsDNA / Au electrode was prepared under the optimal conditions (self-assembly of ssDNA on gold electrode for 14 h at 4 ℃ and hybridization with cDNA at 37 ℃ for 2 h. After DNA damage induced by AFB1 at 37 ℃ for 22 min, The linear range of this method for AFB1 was 10 ~ 500 ng / mL. The spiked recoveries ranged from 95.99% to 104.57%. The established AFB1-induced DNA damage assay enables fast, easy and accurate quantitative detection of AFB1.