Chen Yu, Zhang Fuyuan, Liu Ruobing, Liu Minxuan, Sang Yaxin, Wang Shuo, Wang Xianghong
College of Food Science and Technology, Hebei Agricultural University, Baoding 071001, China.
Medical College, Nankai University, Tianjin 300500, China.
Foods. 2021 Oct 25;10(11):2568. doi: 10.3390/foods10112568.
The detection of aflatoxin B1 (AFB1) has recently garnered much attention on the issue of food safety. In this study, a novel and sensitive aptasensor towards AFB1 is proposed using an Exonuclease III (Exo III)-integrated signal amplification strategy. This reported sensing strategy is regulated by aptamer-functionalized nanobeads that can target AFB1; furthermore, complementary DNA (cDNA) strands can lock the immobilized aptamer strands, preventing the signal amplification function of Exo III in the absence of AFB1. The presence of AFB1 triggers the displacement of cDNA, which will then activate the Exo III-integrated signal amplification procedure, resulting in the generation of a guanine (G)-rich sequence to form a G-4/hemin DNAzyme, which can catalyze the substrate of ABTS to produce a green color. Using this method, a practical detection limit of 0.0032 ng/mL and a dynamic range of detection from 0.0032 to 50 ng/mL were obtained. Additionally, the practical application of the established sensing method for AFB1 in complex matrices was demonstrated through recovery experiments. The recovery rate and relative standard deviations (RSD) in three kinds of cereal samples ranged from 93.83% to 111.58%, and 0.82% to 7.20%, respectively, which were comparable with or better than previously reported methods.
黄曲霉毒素B1（AFB1）的检测最近在食品安全问题上备受关注。在本研究中，提出了一种使用外切核酸酶III（Exo III）整合信号放大策略的新型、灵敏的AFB1适配体传感器。这种报道的传感策略由可靶向AFB1的适配体功能化纳米珠调控；此外，互补DNA（cDNA）链可锁定固定化的适配体链，在不存在AFB1时阻止Exo III的信号放大功能。AFB1的存在触发cDNA的置换，进而激活Exo III整合的信号放大过程，产生富含鸟嘌呤（G）的序列以形成G-4/血红素DNAzyme，其可催化ABTS底物产生绿色。使用该方法，获得了0.0032 ng/mL的实际检测限和0.0032至50 ng/mL的动态检测范围。此外，通过回收率实验证明了所建立的AFB1传感方法在复杂基质中的实际应用。三种谷物样品中的回收率和相对标准偏差（RSD）分别为93.83%至111.58%和0.82%至7.20%，与先前报道的方法相当或更好。
