Since aflatoxin B1 (AFB1) is a highly toxic and carcinogenic secondary metabolite, it is of great importance to develop an effective method for detection of it. Based on hybridization chain reaction (HCR), we proposed a ratiometric dual-signal electrochemical aptasensor (DECA) to realize rapid and sensitive detection of AFB1. In the aptasensor, ferrocene (Fc) and methylene blue (MB)-tagged single-stranded DNA sequences acted as dual-signal sources. Based on this, more stable hairpin DNA (HS-H1) and MB-labeled auxiliary hairpin DNA (H1 and H2) were introduced to extend the sensing platform. In presence of AFB1, it will compete with MB-cDNA and specifically combine with Fc-labeled aptamer. As a result, MB-cDNA will release and trigger the HCR for MB signal amplification with an enhancement in sensitivity. Besides, the ratio of current variations behaved a ratiometric signal output mode. In the proof-of-concept study, the single-signal mode behaved a linear range of 1 pM~10 nM with limit of detection (LOD) of 0.56 pM (I_MB) and 0.15 pM (I_Fc), respectively, while the ratiometric detection mode showed the lowest LOD of 0.12 pM (S/N = 3). The good specificity, reproducibility, and stability of DECA further revealed its promising application in food safety monitoring.

由于黄曲霉毒素B1（AFB1）是一种剧毒、致癌的次级代谢产物，因此开发一种有效的检测方法具有重要意义。基于杂交链式反应（HCR），我们提出了一种比率双信号电化学适体传感器（DECA）来实现AFB1的快速灵敏检测。在适体传感器中，二茂铁 (Fc) 和亚甲蓝 (MB) 标记的单链 DNA 序列充当双信号源。基于此，引入了更稳定的发夹DNA（HS-H1）和MB标记的辅助发夹DNA（H1和H2）来扩展传感平台。在存在 AFB1 的情况下，它将与 MB-cDNA 竞争并与 Fc 标记的适体特异性结合。因此，MB-cDNA 将释放并触发 HCR 以增强 MB 信号放大的灵敏度。除了，电流变化的比率表现为比率信号输出模式。在概念验证研究中，单信号模式的线性范围为 1 pM~10 nM，检测限 (LOD) 为 0.56 pM (I_MB ) 和 0.15 pM (I _Fc )，而比率检测模式显示最低 LOD 为 0.12 pM (S/N = 3)。DECA良好的特异性、重现性和稳定性进一步揭示了其在食品安全监测中的广阔应用前景。