In this work, using DNA and exonuclease-I (Exo-I) as signal amplification strategy, a novel and facile electrochemical aptasensor was constructed for fumonisin B1 (FB1) detection. The G-rich complementary DNA (cDNA) was immobilized onto the electrode surface. Then, aptamer of FB1 was hybridized with cDNA to form double-stranded DNA. In the absence of FB1, double-stranded DNA and G-rich cDNA on the electrode surface promoted effectively methylene blue (MB) enrichment and amplified the initial electrochemical response. In the presence of FB1, the combination of aptamer and FB1 led to the release of aptamer from the electrode surface and the expose of 3′ end of single-stranded cDNA. When Exo-I was added onto the electrode surface, the single-stranded cDNA was degraded in the 3′–5′ direction. The decrease of double-stranded DNA and G-rich cDNA resulted in the less access of MB to the electrode surface, which decreased the electrochemical signal. The experimental conditions including incubation time of FB1, the amount of Exo-I and incubation time of Exo-I were optimized. Under the optimal conditions, the linear relationship between the change of peak current and the logarithmic concentration of FB1 was observed in the range of 1.0 × 10−3–1000 ng mL−1 with a low limit of detection of 0.15 pg mL−1. The experimental results showed that the prepared aptasensor had acceptable specificity, reproducibility, repeatability and stability. Therefore, this proposed aptasensor has a potential application in the food safety detection.

中文翻译：

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使用DNA和核酸外切酶I作为信号放大策略的新型伏马菌素B ₁电化学传感器

在这项工作中，使用DNA和核酸外切酶I（Exo-I）作为信号放大策略，构建了一种新型且简便的电化学伏安菌素B1（FB1）检测适体传感器。将富含G的互补DNA（cDNA）固定在电极表面上。然后，将FB1的适体与cDNA杂交以形成双链DNA。在没有FB1的情况下，电极表面上的双链DNA和富含G的cDNA可以有效地促进亚甲基蓝（MB）的富集并放大初始的电化学反应。在存在FB1的情况下，适体和FB1的组合导致适体从电极表面释放并暴露单链cDNA的3'末端。当将Exo-I添加到电极表面时，单链cDNA沿3'-5'方向降解。双链DNA和富含G的cDNA的减少导致MB较少进入电极表面，从而降低了电化学信号。优化了FB1的孵育时间，Exo-I的量和Exo-I的孵育时间等实验条件。在最佳条件下，观察到峰值电流变化与FB1的对数浓度之间的线性关系，范围为1.0×10-3–1000 ng mL-1，检测下限为0.15 pg mL-1。实验结果表明，所制备的适体传感器具有可接受的特异性，可重复性，可重复性和稳定性。因此，提出的适体传感器在食品安全检测中具有潜在的应用。优化了FB1的孵育时间，Exo-I的量和Exo-I的孵育时间等实验条件。在最佳条件下，观察到峰值电流变化与FB1的对数浓度之间的线性关系，范围为1.0×10-3–1000 ng mL-1，检测下限为0.15 pg mL-1。实验结果表明，所制备的适体传感器具有可接受的特异性，可重复性，可重复性和稳定性。因此，提出的适体传感器在食品安全检测中具有潜在的应用。优化了FB1的孵育时间，Exo-I的量和Exo-I的孵育时间等实验条件。在最佳条件下，观察到峰值电流变化与FB1的对数浓度之间的线性关系，范围为1.0×10-3–1000 ng mL-1，检测下限为0.15 pg mL-1。实验结果表明，所制备的适体传感器具有可接受的特异性，可重复性，可重复性和稳定性。因此，提出的适体传感器在食品安全检测中具有潜在的应用。0×10-3–1000 ng mL-1，检测下限为0.15 pg mL-1。实验结果表明，所制备的适体传感器具有可接受的特异性，可重复性，可重复性和稳定性。因此，提出的适体传感器在食品安全检测中具有潜在的应用。0×10-3–1000 ng mL-1，检测下限为0.15 pg mL-1。实验结果表明，所制备的适体传感器具有可接受的特异性，可重复性，可重复性和稳定性。因此，提出的适体传感器在食品安全检测中具有潜在的应用。