Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
Anal Chem. 2022 May 24;94(20):7191-7199. doi: 10.1021/acs.analchem.1c05440. Epub 2022 May 13.
In this study, upon potassium (K) element doping, the electrochemiluminescence (ECL) excitation potential of graphitic carbon nitride (g-CN) obviously shifted from -1.57 to -0.74 V. Compared with other reported methods, this work was the first one that could reduce the ECL excitation potential of g-CN to below the critical value of -0.9 V. It could more effectively overcome electrode passivation and significantly improve the ECL intensity and stability. Meanwhile, the lower excitation potential could significantly reduce other side reactions caused by high voltage, and the introduction of the K element could obviously increase the water solubility to shorten the preparation time. The apparent decrease of the excitation potential was due to the doping of the K element, which could reduce the band gap, increase the in-plane spacing, and expand π-conjugated systems. Furthermore, using K-doped g-CN with highly stable electrochemiluminescence at lower potential as an emitter, a biosensor for microRNA-141 (miRNA-141) sensitive detection was constructed with the assistance of an innovative nicking enzyme-assisted strand displacement amplification (N-SDA). Compared to the traditional SDA, a nicking enzyme was introduced to obviously improve the utilization rate of the fuel chain and increase the number of cycles, finally resulting in higher signal amplification efficiency. Therefore, the constructed biosensor showed excellent performance in the ultrasensitive detection of miRNA-141 with the limit of detection (LOD) being 44.8 aM. This work gave a more effective means to obviously improve the ECL property of g-CN caused by electrode passivation and provided a more efficient and convenient detection method for biochemical analysis.
在这项研究中，通过钾（K）元素掺杂，石墨相氮化碳（g-CN）的电化学发光（ECL）激发电位明显从-1.57 变为-0.74 V。与其他报道的方法相比，这项工作首次将 g-CN 的 ECL 激发电位降低到低于-0.9 V 的临界值以下。它可以更有效地克服电极钝化，显著提高 ECL 强度和稳定性。同时，较低的激发电位可以显著减少高压引起的其他副反应，而 K 元素的引入可以明显提高水溶性，缩短制备时间。激发电位的明显降低归因于 K 元素的掺杂，它可以降低带隙、增加层内间距并扩展π共轭体系。此外，使用具有较低电位下高度稳定电化学发光的 K 掺杂 g-CN 作为发射器，通过引入一种创新的核酸酶辅助链置换扩增（N-SDA），构建了用于 microRNA-141（miRNA-141）灵敏检测的生物传感器。与传统的 SDA 相比，引入了一种核酸酶，明显提高了燃料链的利用率并增加了循环次数，最终实现了更高的信号放大效率。因此，所构建的生物传感器在 miRNA-141 的超灵敏检测中表现出优异的性能，检测限（LOD）为 44.8 aM。这项工作为明显改善因电极钝化引起的 g-CN 的 ECL 性能提供了更有效的手段，并为生化分析提供了更高效、更便捷的检测方法。
