Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, School of Agricultural Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
Anal Chem. 2022 Jan 18;94(2):1294-1301. doi: 10.1021/acs.analchem.1c04501. Epub 2021 Dec 29.
Ferrocene (Fc) is a common quencher of Ru(bpy) luminescence. However, interactions between Fc and Ru(bpy) can be extremely complicated. In this work, we reported the first use of Fc to regulate the electrochemiluminescence (ECL) of Ru(bpy) by tuning the length of the DNA sequence between Fc and the luminophore of nitrogen-doped graphene quantum dots-Ru(bpy)-doped silica nanoparticles (SiO@Ru-NGQDs). The ECL of SiO@Ru-NGQDs was depressed when the distance between Ru(bpy) and Fc was less than 8 nm; a stronger ECL was observed when the distance was more than 12 nm. The switching of the ECL of Ru(bpy) by Fc was attributed to the electron transfer mechanism, in which Fc participated in the redox of Ru(bpy) for "signal-off" ECL; this favored electron transfer at the electrode fabricated with an Fc-labeled aptamer (Fc-apt) and SiO@Ru-NGQDs for "signal-on" ECL depending on the length of the DNA sequence. Here, a dual-signal readout aptasensor for aflatoxin B1 (AFB1) detection was developed via the enhanced ECL of SiO@Ru-NGQDs by Fc-apt. The redox currents of Fc and the ECL of Ru(bpy) were simultaneously collected as yardsticks, and both decreased with higher concentrations of AFB1. The aptasensor allowed linear ranges of 3 × 10 to 1 × 10 ng mL for ECL mode and 1 × 10 to 3 × 10 ng mL for electrochemical mode. Our work provides insight into the interactions between Fc and Ru(bpy). The dual-signal readout strategy is a potential platform for the versatile design of aptasensors.
二茂铁（Fc）是一种常见的钌（bpy）发光体猝灭剂。然而，Fc 与 Ru(bpy) 之间的相互作用可能非常复杂。在这项工作中，我们首次报道了通过调节 Fc 和氮掺杂石墨烯量子点-Ru(bpy)-掺杂二氧化硅纳米粒子（SiO@Ru-NGQDs）的发光体之间的 DNA 序列长度，用 Fc 来调节 Ru(bpy) 的电化学发光（ECL）。当 Ru(bpy) 和 Fc 之间的距离小于 8nm 时，SiO@Ru-NGQDs 的 ECL 被抑制；当距离大于 12nm 时，观察到更强的 ECL。Fc 对 Ru(bpy) 的 ECL 的开关归因于电子转移机制，其中 Fc 参与 Ru(bpy) 的氧化还原反应，用于“信号关闭”ECL；这有利于在带有 Fc 标记的适体（Fc-apt）和 SiO@Ru-NGQDs 的电极上进行电子转移，用于“信号开启”ECL，这取决于 DNA 序列的长度。在这里，通过 Fc-apt 增强 SiO@Ru-NGQDs 的 ECL，开发了用于检测黄曲霉毒素 B1（AFB1）的双信号读出适体传感器。Fc 的氧化还原电流和 Ru(bpy) 的 ECL 同时被收集作为标准，两者都随着 AFB1 浓度的增加而降低。该适体传感器在 ECL 模式下的线性范围为 3×10 至 1×10ng mL，在电化学模式下的线性范围为 1×10 至 3×10ng mL。我们的工作提供了对 Fc 和 Ru(bpy) 之间相互作用的深入了解。双信号读出策略是适体传感器多功能设计的潜在平台。
