Gupta Vanshika, Pham AnhThu, Dick Jeffrey E
Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States.
Anal Chem. 2024 Aug 17. doi: 10.1021/acs.analchem.4c01043.
Electrochemical aptamer-based sensors provide a highly modular platform for real-time monitoring of small molecules. Their ability to selectively recognize target molecules in complex environments like biological fluids makes them an attractive technology for the analysis of micro- and nanoscale systems. The signal-to-noise of the measurement depends on the electroactive surface (i.e., how many aptamers one can place), which has previously precluded miniaturization of aptamer-based sensors to planar disk ultramicroelectrodes ( ∼ 5-10 μm). Here, we employ a concentration enrichment strategy based on the active dissolution of an aqueous, aptamer-containing microdroplet on an ultramicroelectrode submerged in an organic continuous phase (1,2-dichloroethane). We show consistent voltammetric signal increase as a function of droplet lifetime, indicating the successful immobalization of the thiol-terminated aminoglycoside aptamers to the electrode surface. We observe a diagnostic methylene blue peak and 10-fold increase in current magnitude as compared to bare microelectrodes. We report robust sensor behavior with a linear dynamic range extending from milli- to micromolar concentrations of kanamycin in buffer. This research offers a successful method for optimized electrochemical aptamer-based sensor fabrication and miniaturization on ultramicroelectrodes without the need for electrode surface area enhancement.
基于电化学适配体的传感器为小分子的实时监测提供了一个高度模块化的平台。它们能够在生物流体等复杂环境中选择性识别目标分子，这使其成为用于分析微纳尺度系统的一项有吸引力的技术。测量的信噪比取决于电活性表面（即能够放置多少适配体），这一点此前阻碍了基于适配体的传感器向平面圆盘超微电极（约5 - 10μm）的小型化发展。在此，我们采用了一种浓度富集策略，该策略基于浸没在有机连续相（1,2 - 二氯乙烷）中的超微电极上含适配体的水性微滴的主动溶解。我们展示了伏安信号随微滴寿命的延长而持续增加，这表明巯基化氨基糖苷适配体成功固定到了电极表面。与裸微电极相比，我们观察到了诊断性的亚甲基蓝峰以及电流大小增加了10倍。我们报道了在缓冲液中对卡那霉素具有从毫摩尔到微摩尔浓度范围的线性动态范围的稳健传感器行为。这项研究提供了一种成功的方法，用于在无需增大电极表面积的情况下，在超微电极上优化基于电化学适配体的传感器制造及小型化。
