Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Anal Chem. 2020 Nov 17;92(22):15112-15119. doi: 10.1021/acs.analchem.0c03311. Epub 2020 Oct 27.
In this study, sulfur quantum dots (SQDs) with superior near-infrared electrochemiluminescence (ECL) performance were synthesized by the HO-assisted top-down approach. Through HO etching, the size and dispersity of SQDs were adjusted, reducing the aggregation-caused quenching effect and obviously promoting the ECL performance. Using the obtained SQDs as an emitter, a super-sensitive ECL biosensor of microRNA-21 (miRNA-21) detection was constructed, which was based on an efficient DNA walking machine with triple-stranded DNA (tsDNA) nanostructures as tracks. Compared with the common single-stranded DNA or double-stranded DNA, the tsDNA nanostructures on the electrode interface could avert probe entanglement and decrease local overcrowding effects. The walking efficiency of the DNA walking machine was also improved and the signal-amplification efficacy was greatly enhanced, which was benefited from the fact that tsDNA nanostructures were highly rigid scaffolds and provided orderly tracks for the DNA walking machine to walk. Thus, the designed ECL biosensor demonstrated outstanding performance for miRNA-21 detection in the concentration range of 20 aM to 1 nM with a low detection limit of 6.67 aM. Remarkably, this work enriched the application of pure element quantum dots in the ECL field and offered a new avenue for ultra-sensitive detection in clinical and biochemical analysis.
在这项研究中，通过 HO 辅助的自上而下法合成了具有优异近红外电化学发光（ECL）性能的硫量子点（SQDs）。通过 HO 刻蚀，调整了 SQDs 的尺寸和分散性，减少了聚集引起的猝灭效应，明显提高了 ECL 性能。将得到的 SQDs 用作发射器，构建了基于具有三链 DNA（tsDNA）纳米结构作为轨道的高效 DNA 行走机器的超灵敏 miRNA-21（miRNA-21）检测 ECL 生物传感器。与常见的单链 DNA 或双链 DNA 相比，电极界面上的 tsDNA 纳米结构可以避免探针缠结并减少局部过度拥挤效应。DNA 行走机器的行走效率也得到了提高，信号放大效果大大增强，这得益于 tsDNA 纳米结构是高度刚性的支架，并为 DNA 行走机器的行走提供了有序的轨道。因此，所设计的 ECL 生物传感器在 20 aM 至 1 nM 的浓度范围内对 miRNA-21 的检测表现出优异的性能，检测限低至 6.67 aM。值得注意的是，这项工作丰富了纯元素量子点在 ECL 领域的应用，为临床和生化分析中的超灵敏检测提供了新途径。
