School of Food Science and Technology, Henan University of Technology, Lianhua Road 100#, Zhengzhou 450001, Henan Province, People's Republic of China.
ACS Appl Mater Interfaces. 2022 Jun 1;14(21):24681-24689. doi: 10.1021/acsami.2c03234. Epub 2022 May 17.
The abuse of chloramphenicol (CAP) in animal-derived products leads to serious food safety problems, so the sensitive and accurate determination of CAP residues has great noteworthiness for public health. Herein, we present a novel electrochemical aptasensor that incorporates a poly(diallyldimethylammonium chloride) functionalized graphene/Ag@Au nanosheets (PDDA-Gr/Ag@Au NSs) composite modified electrode and a DNAzyme signal amplification effect triggered by a triple-helix molecular switch (THMS) for detecting CAP. The PDDA-Gr/Ag@Au NSs composite has the advantages of high surface area, great conductivity, and dispersibility and has successfully improved the electrochemical performance of the electrode. Specific interaction with CAP will cause the signal transduction probe (STP) to be released from the THMS. After that, the DNAzyme will be activated with the help of Pb and remove the immobilized signal probe on the electrode surface. The signal change was recorded by square wave voltammetry (SWV) and led to an accurate quantification of CAP. With all these features, the proposed sensing strategy yielded a satisfactory analytical performance with linearity between 1 pM and 1 μM and a limit of detection of 18.6 fM. Furthermore, the aptasensor shows excellent specificity for CAP in the presence of other antibiotics and resists interference with other common metal ions. Importantly, the performance is not diminished when the constructed aptasensor is applied to measuring CAP in milk powder. This THMS-based method is easy to design, and alteration to different targets can be achieved by simply replacing the aptamer sequence in the THMS. Therefore, this method shows significant prospects as a flexible platform for accurate monitoring of antibiotic residues in foodstuffs.
氯霉素（CAP）在动物源性产品中的滥用导致了严重的食品安全问题，因此，CAP 残留的灵敏准确测定对公众健康具有重要意义。在此，我们提出了一种新型电化学适体传感器，该传感器结合了聚二烯丙基二甲基氯化铵功能化石墨烯/Ag@Au 纳米片（PDDA-Gr/Ag@Au NSs）复合修饰电极和由三链体分子开关（THMS）触发的 DNA 酶信号放大效应，用于检测 CAP。PDDA-Gr/Ag@Au NSs 复合具有高表面积、高导电性和分散性的优点，成功改善了电极的电化学性能。与 CAP 的特异性相互作用会导致信号转导探针（STP）从 THMS 中释放出来。之后，在 Pb 的帮助下，DNA 酶将被激活，并从电极表面去除固定化的信号探针。通过方波伏安法（SWV）记录信号变化，从而实现对 CAP 的准确定量。具有所有这些特征的传感策略表现出令人满意的分析性能，线性范围为 1 pM 至 1 μM，检测限为 18.6 fM。此外，该适体传感器在存在其他抗生素的情况下对 CAP 表现出优异的特异性，并能抵抗其他常见金属离子的干扰。重要的是，当将构建的适体传感器应用于测量奶粉中的 CAP 时，其性能不会降低。这种基于 THMS 的方法易于设计，并且通过简单地替换 THMS 中的适体序列，可以实现对不同靶标的改变。因此，该方法作为一种用于准确监测食品中抗生素残留的灵活平台具有重要的应用前景。
