State Key Laboratory Base of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, China.
Anal Chem. 2012 Mar 20;84(6):2811-7. doi: 10.1021/ac203261x. Epub 2012 Mar 6.
A novel small magnetic electrochemiluminescent Fe(3)O(4)@CdSe composite quantum dot (QD) was facilely prepared and successfully applied to sensitive electrochemiluminescence (ECL) detection of thrombin by a multiple DNA cycle amplification strategy for the first time. The as-prepared composite QDs feature intense ECL, excellent magnetism, strong fluorescence, and favorable biocompatibility, which offers promising advantages for ECL biosensing. ECL of the composite QDs was efficiently quenched by gold nanoparticles (NPs). Taking advantages of the unique and attractive ECL and magnetic characteristics of the composite QDs, a novel DNA-amplified detection method based on ECL quenching was thus developed for a sensitive assay of thrombin. More importantly, the DNA devices by cleavage reaction were cycled multiple rounds, which greatly amplified the ECL signal and much improve the detection sensitivity. This flexible biosensing system exhibits not only high sensitivity and specificity but also excellent performance in real human serum assay. The present work opens a promising approach to develop magnetic quantum dot-based amplified ECL bioassays, which has wider potential application with more favorable analytical performances than other ECL reagent-based systems. Moreover, the composite QDs are suitable for long-term fluorescent cellular imaging, which also highlights the promising directions for further development of QD-based in vitro and in vivo imaging materials.
一种新型的小磁性电化学发光 Fe(3)O(4)@CdSe 复合量子点（QD）被简便地制备出来，并首次通过多重 DNA 循环扩增策略成功地应用于灵敏的电化学发光（ECL）检测凝血酶。所制备的复合 QD 具有强烈的 ECL、优异的磁性、强荧光和良好的生物相容性，为 ECL 生物传感提供了有前途的优势。复合 QD 的 ECL 被金纳米粒子（NPs）有效地猝灭。利用复合 QD 的独特而有吸引力的 ECL 和磁性特性，因此开发了一种基于 ECL 猝灭的新型 DNA 放大检测方法，用于灵敏检测凝血酶。更重要的是，通过切割反应的 DNA 器件可以循环多个回合，这大大放大了 ECL 信号，极大地提高了检测灵敏度。该灵活的生物传感系统不仅表现出高灵敏度和特异性，而且在真实的人血清测定中也表现出优异的性能。本工作为开发基于磁性量子点的放大 ECL 生物分析方法开辟了一条有前途的途径，与其他基于 ECL 试剂的系统相比，它具有更广泛的潜在应用和更有利的分析性能。此外，复合 QD 适用于长期荧光细胞成像，这也突出了基于 QD 的体外和体内成像材料进一步发展的有希望的方向。
