Microchimica Acta ( IF 5.3 ) Pub Date : 2021-08-04 , DOI: 10.1007/s00604-021-04912-z Youxiong Zhang 1 , Bing Li 1, 2 , Xianhu Wei 1 , Qihui Gu 1 , Moutong Chen 1 , Jumei Zhang 1 , Shuping Mo 1 , Liang Xue 1 , Qingping Wu 1 , Juan Wang 2 , Yu Ding 3
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A facile and versatile competitive electrochemical aptasensor for tobramycin (TOB) detection is described using electrochemical-deposited AuNPs coordinated with PEI-functionalized Fe-based metal-organic framework (AuNPs/P-MOF) as signal-amplification platform and a DNA probe labeled with methylene blue (MB) at the 3′-end (MB-Probe) as a signal producer. First, F-Probe (short complementary DNA strands of both the aptamer and the MB-Probe label with a sulfhydryl group at the 5′-end) was immobilized on the AuNPs/P-MOF modified electrode as detection probes, which competed with TOB in binding to the aptamer. TOB-aptamer binding resulted in F-Probe remaining unhybridized on the electrode surface, so that a significant current response was generated by hybridizing with MB-Probe instead. The developed strategy showed favorable repeatability, with a relative standard deviation (RSD) of 4.3% computed over five independent assays, and high stability, with only 6.8% degradation after 15 days of storage. Under optimal conditions, the proposed aptamer strategy exhibited a linear detection range from 100 pM to 500 nM with a limit of detection (LOD) of 56 pM (S/N = 3). The electrochemical aptasensor demonstrated remarkable selectivity, and its feasibility for accurate and quantitative detection of TOB in milk samples was confirmed (RSD < 4.5%). Due to its simple design, easy operation, and high sensitivity and selectivity, the proposed method could expect to detect other antibiotics by replacing the aptamers. In summary, this study provides a simple and effective new strategy for electrochemical aptasening based on MOF-based sensing interface.
Graphical abstract
中文翻译：
基于电化学沉积的 AuNPs 与 PEI 功能化的 Fe 基金属有机框架配合的放大电化学抗生素适体传感
使用电化学沉积的 AuNPs 与 PEI 功能化的 Fe 基金属有机框架 (AuNPs/P-MOF) 作为信号放大平台和标记有3' 端的亚甲蓝 (MB) (MB-Probe) 作为信号生成器。首先，将 F-Probe（适体和 MB-Probe 标记的短互补 DNA 链在 5'-末端带有巯基）固定在 AuNPs/P-MOF 修饰电极上作为检测探针，与 TOB 竞争与适体结合。TOB-适配体结合导致 F-Probe 在电极表面上保持未杂交，因此通过与 MB-Probe 杂交产生显着的电流响应。开发的策略显示出良好的可重复性，5 次独立测定的相对标准偏差 (RSD) 为 4.3%，稳定性高，储存 15 天后降解率仅为 6.8%。在最佳条件下，所提出的适体策略表现出从 100 pM 到 500 nM 的线性检测范围，检测限 (LOD) 为 56 pM (S/N = 3）。电化学适体传感器表现出显着的选择性，并证实了其在牛奶样品中准确定量检测 TOB 的可行性（RSD < 4.5%）。由于其设计简单、操作方便、灵敏度和选择性高，该方法有望通过替换适体来检测其他抗生素。总之，本研究为基于 MOF 传感界面的电化学适配提供了一种简单有效的新策略。
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