Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power, Shanghai University of Electric Power, Shanghai 200090, China.
Anal Methods. 2024 Jun 27;16(25):4160-4167. doi: 10.1039/d4ay00830h.
This study proposes a strategy using a microfluidic ratiometric electrochemical aptasensor to detect PCB77 with excellent sensitivity and specificity. This sensing platform combines a microfluidic chip, a wireless integrated circuit system for aptamer-based electrochemical detection, and a mobile phone control terminal for parameter configuration, identification, observation, and wireless data transfer. The sensing method utilizes a cDNA (MB-COOH-cDNA-SH) that is labelled with the redox probe Methylene Blue (MB) at the 5' end and has a thiol group at the 3' end. Additionally, it utilizes a single strand PCB aptamer that has been modified with ferrocenes at the 3' end (aptamer-Fc). Through gold-thiol binding, the labelled probe of MB-COOH-cDNA-SH was self-assembled onto the surface of an Au/NbCT/GO modified electrode. On exposure to aptamer-Fc, it will hybridize with MB-COOH-cDNA-SH to form a stable double-stranded structure on the electrode surface. When PCB77 is present, aptamer-Fc binds specifically to the target, enabling the double-stranded DNA to unwind. Such variation caused changes in the differential pulse voltammetry (DPV) peak currents of both MB and Fc. A substantial improvement is observed in the ratio between the two DPV peaks. Under the optimum experimental conditions, this assay has a response that covers the 0.0001 to 1000 ng mL PCB77 concentration range, and the detection limit is 1.56 × 10 ng mL. The integration of a ratiometric electrochemical aptasensor with designed microfluidic and integrated devices in this work is an innovative and promising approach that offers an efficient platform for on-site applications.
本研究提出了一种使用微流控比率电化学适体传感器检测 PCB77 的策略，该策略具有出色的灵敏度和特异性。该传感平台结合了微流控芯片、基于适体的电化学检测用无线集成电路系统以及用于参数配置、识别、观察和无线数据传输的手机控制终端。传感方法利用在 5'端标记有氧化还原探针亚甲蓝 (MB) 且在 3'端具有巯基的 cDNA (MB-COOH-cDNA-SH)。此外，它还利用了在 3'端修饰有二茂铁的单链 PCB 适体 (aptamer-Fc)。通过金-硫键结合，MB-COOH-cDNA-SH 的标记探针自组装到 Au/NbCT/GO 修饰电极的表面上。当暴露于 aptamer-Fc 时，它将与 MB-COOH-cDNA-SH 杂交，在电极表面上形成稳定的双链结构。当存在 PCB77 时，aptamer-Fc 特异性地与靶标结合，使双链 DNA 解旋。这种变化导致 MB 和 Fc 的差分脉冲伏安法 (DPV) 峰电流发生变化。两个 DPV 峰之间的比率有显著提高。在最佳实验条件下，该测定法在 0.0001 至 1000 ng mL PCB77 浓度范围内有响应，检测限为 1.56×10 ng mL。本工作中将比率电化学适体传感器与设计的微流控和集成器件集成在一起，是一种创新且有前途的方法，为现场应用提供了高效的平台。
