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本文采用银染增强金纳米粒子(Au NPs)为信号因子,构建了一种新型的灵敏检测羟基自由基(·OH)的DNA电化学传感器.首先,巯基化的DNA1通过Au—S键自组装于金基底电极表面.然后,由Fenton反应产生的·OH可引起电极表面DNA1自组装层的氧化损伤裂解,未损伤的DNA1可与功能化Au NPs上的DNA2杂交.利用Au NPs对银离子的催化还原反应,将银原子沉积在Au NPs的周围,形成一层银外壳,再用差分脉冲伏安法(DPV)技术对沉积的银进行电化学检测,从而实现·OH的定量分析.研究结果表明,在最优实验条件下,该传感器检测·OH的线性范围为0.2~200μmol·L-1,检测下限为50 nmol·L-1.该传感器有较好的重复性、选择性,并在抗氧化剂抗氧化能力评估方面具有潜在应用价值.
In this paper, a new type of DNA electrochemical sensor for sensitive detection of hydroxyl radicals (· OH) was constructed by using silver-enhanced gold nanoparticles (Au NPs) as signal factors.Firstly, the thiolated DNA1 was self-assembled by Au-S bonds · OH generated by Fenton reaction could be oxidatively damaged and cleaved by the self-assembled layer of DNA1 on the electrode surface, and unimpaired DNA1 could hybridize with DNA2 on the functionalized Au NPs. Catalytic reduction reaction, the silver atoms were deposited around the Au NPs to form a silver shell, and then the differential pulse voltammetry (DPV) was used to electrochemically detect the deposited silver to achieve · OH quantitative analysis. The results showed that the linear range of this sensor was 0.2 ~ 200μmol·L-1 and the detection limit was 50 nmol·L-1 under the optimal experimental conditions.The sensor has good repeatability and selectivity, Antioxidant antioxidant capacity evaluation has potential application value.