To enhance the effects of some functional soft drinks, drugs, especially metronidazole (MNZ) and ibuprofen (IBF), are often illegally added. This poses a serious threat to the health of consumers. Therefore, developing simple and rapid detection methods for these additives is crucial. In this study, DNA aptamers of metronidazole and ibuprofen were selected using the library-immobilized method. The best aptamer for metronidazole, named MNZ-1, has a dissociation constant (K_d) value of 4.9 μM and the aptamer for ibuprofen, named IBF-1, shows a K_d of 9.3 μM, as determined by the thioflavin T (ThT) fluorescence assay. The K_d values measured using isothermal titration calorimetry (ITC) were 17.0 μM and 66.7 μM for these two aptamers, respectively. Selectivity experiments indicate that MNZ-1 demonstrates very weak binding to structurally similar drugs, whereas IBF-1 exhibits binding capability to some structurally similar compounds comparable to ibuprofen, enabling the simultaneous detection of these types of drugs. Neither MNZ-1 nor IBF-1 binds to other common drugs. Using ThT, a label-free fluorescent detection method was developed for metronidazole and ibuprofen in soft drinks, showing limits of detection (LODs) of 0.6 μM and 4.7 μM, respectively. Owing to their small size and well-defined secondary structures, these aptamers are expected to be utilized in analytical applications for food and environmental monitoring.

中文翻译：

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用于检测甲硝唑和布洛芬的 DNA 适配体的选择：软饮料中的两种常见添加剂


为了增强某些功能性软饮料的效果，经常非法添加药物，尤其是甲硝唑 （MNZ） 和布洛芬 （IBF）。这对消费者的健康构成了严重威胁。因此，为这些添加剂开发简单快速的检测方法至关重要。在本研究中，使用文库固定化方法选择甲硝唑和布洛芬的 DNA 适体。甲硝唑的最佳适配体 MNZ-1 的解离常数 （K_d） 值为 4.9 μM，布洛芬适配体 IBF-1 的 K_d 为 9.3 μM，通过硫黄素 T （ThT） 荧光测定法测定。使用等温滴定量热法 （ITC） 测得的这两种适配子的 K_d 值分别为 17.0 μM 和 66.7 μM。选择性实验表明，MNZ-1 与结构相似药物的结合非常弱，而 IBF-1 与一些结构相似的化合物的结合能力与布洛芬相当，能够同时检测这些类型的药物。MNZ-1 和 IBF-1 均不与其他常见药物结合。使用 ThT，开发了一种针对软饮料中甲硝唑和布洛芬的无标记荧光检测方法，检测限 （LOD） 分别为 0.6 μM 和 4.7 μM。由于体积小且二级结构明确，这些适配体有望用于食品和环境监测的分析应用。