Key Laboratory of Modern Agricultural Equipment and Technology (Jiangsu University), Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
Key Laboratory of Modern Agricultural Equipment and Technology (Jiangsu University), Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; School of Emergency Management, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
Sci Total Environ. 2023 Nov 20;900:166407. doi: 10.1016/j.scitotenv.2023.166407. Epub 2023 Aug 18.
Aptamers with strong affinity to heavy metal ions (HMIs) allow fabrication of electrochemical sensors with high selectivity and sensitivity, while controllable regulation of aptamer-HMI recognition at the sensing interface, which is vital for better analytical performance, remains challenging. Here, an electric field-based strategy for engineering an aptasensing interface was proposed to realize the specific preconcentration and accurate detection of mercury (Hg) and lead (Pb) ions with a ratiometric electrochemical sensor. The working principle is to apply an electric field to drive HMIs to approach the aptamer and retain the orientation of the DNA structure. Anthraquinone-2-carboxylic acid (AQ)-labeled complementary DNA was designed to simultaneously bind a ferrocene (Fc)-labeled aptamer for Hg and a methylene blue (MB)-labeled aptamer for Pb, and the sensing interface was fabricated with this presynthesized DNA structure. For preconcentration, an electric field of 3.0 V pushed HMIs to approach the aptamer and retained the orientation of DNA to favor the following recognition; for detection, the oriented DNA in 2.5 V electric field offered a stable current of AQ as a reference. In this way, currents of AQ, Fc and MB were used to produce ratiometric signals of I/I and I/I for Hg and Pb, respectively. Such a strategy allowed the simultaneous detection of Hg and Pb within 30 min with detection limits of 0.69 pM and 0.093 pM, respectively. The aptasensor was applied for soil, water, and crayfish analysis in paddy fields. The electric field-enabled strategy offers a new way to fabricate high-performance electrochemical aptasensor for HMIs detection.
适配子与重金属离子 (HMIs) 具有很强的亲和力，可用于制造具有高选择性和灵敏度的电化学传感器，而在传感界面上对适配子-HMI 识别进行可控调节对于获得更好的分析性能至关重要，但这仍然具有挑战性。在这里，提出了一种基于电场的策略来构建适体传感界面，以实现汞 (Hg) 和铅 (Pb) 离子的特异性预浓缩和准确检测，具有比率型电化学传感器。其工作原理是施加电场以驱动 HMIs 接近适配子并保持 DNA 结构的取向。设计了蒽醌-2-羧酸 (AQ)-标记的互补 DNA，以同时结合带有二茂铁 (Fc) 标记的适体用于 Hg 和带有亚甲蓝 (MB) 标记的适体用于 Pb，并使用这种预合成的 DNA 结构构建传感界面。用于预浓缩，施加 3.0 V 的电场将 HMIs 推向适配子并保持 DNA 的取向以有利于随后的识别；用于检测，在 2.5 V 电场中，取向的 DNA 提供了稳定的 AQ 电流作为参考。通过这种方式，AQ、Fc 和 MB 的电流用于分别产生 Hg 和 Pb 的比率信号 I/I 和 I/I。这种策略允许在 30 分钟内同时检测 Hg 和 Pb，检测限分别为 0.69 pM 和 0.093 pM。该适体传感器已应用于稻田土壤、水和小龙虾分析。电场使能策略为 HMIs 检测提供了一种制造高性能电化学适体传感器的新方法。
