基于DNA四面体纳米结构探针的电化学生物传感器检测DNA甲基化

该文以DNA四面体纳米结构探针(TSP)为捕获探针，将辣根过氧化物酶标记的IgG抗体结合在纳米金颗粒表面(AuNPs-IgG-HRP)作为信号分子，构建了一种新型DNA甲基化电化学传感器。利用一步热变性法组装成TSP后，通过Au—S键固定在修饰纳米金颗粒的金电极表面，经过靶标DNA杂交、5-甲基胞嘧啶(5-mc)抗体及AuNPs-IgG-HRP结合后，用差分脉冲伏安法(DPV)进行检测。采用循环伏安法(CV)和电化学阻抗谱(EIS)对修饰电极的构建过程进行电化学表征。探究了杂交时间、5-mc抗体浓度、IgG-HRP加入体积、氢醌(HQ)和过氧化氢(H2O2)浓度对传感器的影响。在最佳条件下，该传感器对甲基化DNA的线性响应范围为1.0×10-15~1.0×10-10 mol/L，检出限(S/N=3)为4.4×10-16 mol/L。该传感器具有良好的选择性和稳定性，为DNA甲基化检测提供了新方法。

An Electrochemical Biosensor Based on a DNA Tetrahedral Nanostructure Probe for Detection of DNA Methylation

In this study,a novel electrochemical sensor was constructed for the detection of DNA methylation,with a DNA tetrahedral nanostructure probe(TSP) as capture probe and horseradish peroxidase-labeled IgG antibody bound to the surface of gold nanoparticles (AuNPs-IgG-HRP) as a signal molecule.After being assembled into TSP by the one step thermal denaturation method,the probe was fixed on the surface of AuNPs/AuE electrode through Au-S bond.Experienced the target DNA hybridization,5-methylcytosine (5-mc) antibody and AuNPs-IgG-HRP conjugation,the electrochemical signal was obtained by differential pulse voltammetry(DPV).The construction process of the modified electrode was characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS).Effects of hybridization time,5-mc antibody concentration,addition volume of IgG-HRP,concentrations of hydroquinone(HQ) and hydrogen peroxide(H2O2) on the sensor were explored.Under the optimal conditions,the biosensor exhibited a good linear response toward the methylated DNA in the range of 1.0×10-15-1.0×10-10 mol/L,with a detection limit (S/N=3) of 4.4×10-16 mol/L.The biosensor could provide a new method for the detection of DNA methylation with good selectivity and stability.