The simultaneous detection of multiple mycotoxins in grains is significant due to the enhanced toxicity induced by their synergistic effects. In this work, a dual-ratiometric electrochemical aptasensing strategy for the simultaneous detection of aflatoxin B1 (AFB1) and ochratoxin A (OTA) was developed. Here, an anthraquinone-2-carboxylic acid (AQ)-labelled complementary DNA (cDNA) was used to provide separate and specific binding sites to assemble the ferrocene-labelled AFB1 aptamer (Fc-Apt1) and methylene blue-labelled OTA aptamer (MB-Apt2). The target-induced current ratios of I_Fc/I_AQ and I_MB/I_AQ were then used to quantitatively relate to AFB1 and OTA, respectively. Following this principle, two types of aptasensors involving the hairpin DNA (hDNA) and linear single-stranded DNA (ssDNA) as the cDNA were fabricated for performance comparisons. The results revealed that hairpin DNA with a rigid 2D structure can greatly improve the assembly and recognition efficiency of the sensing interface, which makes the hDNA-based aptasensor possess high sensitivity, reliability and anti-interference ability. The hDNA-based aptasensor exhibited a detection range of 10-3000 pg mL⁻¹ for AFB1 and 30-10000 pg mL⁻¹ for OTA, respectively, with no observable cross-reactivity. Furthermore, the aptasensor was applied to analyze corn and wheat samples, and the reliability was validated by HPLC-MS/MS. Our work has presented a novel way for fabricating a high-performance aptasensor for simultaneous detection of multiple mycotoxins.

谷物中多种霉菌毒素的同时检测具有重要意义，因为它们的协同作用增强了毒性。在这项工作中，开发了一种用于同时检测黄曲霉毒素B1（AFB1）和曲霉毒素A（OTA）的双比例电化学适配策略。在这里，蒽醌-2-羧酸（AQ）标记的互补DNA（cDNA）用于提供单独的特异性结合位点，以组装二茂铁标记的AFB1适体（Fc-Apt1）和亚甲基蓝标记的OTA适体（MB -Apt2）。目标感应电流比I _Fc / I _AQ和I _MB / I _AQ然后分别用于定量关联AFB1和OTA。遵循这一原理，制造了两种类型的适体传感器，涉及发夹DNA（hDNA）和线性单链DNA（ssDNA）作为cDNA，以进行性能比较。结果表明，具有刚性2D结构的发夹DNA可以大大提高传感界面的组装和识别效率，这使得基于hDNA的适体传感器具有很高的灵敏度，可靠性和抗干扰能力。基于hDNA的适体传感器对AFB1的检测范围为10-3000 pg mL ^-1，在30-10000 pg mL ^-1下对于OTA，分别没有明显的交叉反应性。此外，将适体传感器用于分析玉米和小麦样品，并通过HPLC-MS / MS验证了其可靠性。我们的工作提出了一种新颖的方法，可以制造用于同时检测多种霉菌毒素的高性能适体传感器。