基于酶辅助靶标循环的适体传感器灵敏检测中药中黄曲霉毒素B1

该文基于酶辅助靶标循环信号放大策略构建了用于黄曲霉毒素B1(AFB1)高灵敏检测的化学发光适体传感器。以G-四链体/氯化血红素DNA酶为信号分子设计了免标记的适体探针H1-S1和发夹探针H2。适体探针结合目标AFB1,在核酸外切酶I辅助下,触发靶标循环反应产生发夹H1。发夹H1与H2杂交,释放出完整的G-四链体序列,并进一步与氯化血红素结合形成G-四链体/氯化血红素DNA酶。DNA酶通过催化氧化鲁米诺-H2O2化学发光体系产生化学发光信号,实现AFB1的放大检测。在最优实验条件下,化学发光强度与AFB1质量浓度的对数在0.001~100 ng/mL范围内呈良好的线性关系,相关系数(r2)为0.9955,检出限为0.93 pg/mL,回收率为93.7%~107%。该适体传感器操作简单、灵敏度高、特异性好,在黄曲霉毒素污染检测方面具有良好的应用前景。

Sensitive Detection of Aflatoxin B1 in Traditional Chinese Medicine Using an Aptasensor Based on Enzyme-assisted Target Recycling

In this paper,a chemiluminescence aptasensor for the highly sensitive detection of aflatoxin B1(AFB1)was constructed based on the strategy of enzyme-assisted target recycling amplification.The label-free aptamer probe H1-S1 and hairpin probe H2 were well designed using G-quadruplex/hemin DNAzyme as the signal molecule.The aptamer probe bound to the target AFB1,which triggered the target recycling amplification reaction with the help of exonuclease I to generate hairpin H1.The hairpin H1 was hybridized with H2,releasing the complete G-quadruplex sequence.The G-quadruplex sequence combined with hemin to form G-quadruplex/hemin DNAzyme,which catalyzed the oxidation of luminol-H2O2 chemiluminescence system to generate chemiluminescence signals to achieve the amplified detection of AFB1.Under the optimal experimental conditions,the chemiluminescence intensity exhibited a good linear relationship(r2=0.9955)with the logarithm of AFB1 concentration in the range of 0.001-100 ng/mL.The detection limit was 0.93 pg/mL,and the recoveries were in the range of 93.7%-107%.With the advantages of simple operation,high sensitivity and good specificity,this aptasensor has a good application prospect in the detection of aflatoxin contamination.