Signal-Amplified Near-Infrared Ratiometric Electrochemiluminescence Aptasensor Based on Multiple Quenching and Enhancement Effect of Graphene/Gold Nanorods/G-Quadruplex

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• 作者：Kang Shao ; Biru Wang ; Shiyi Ye ; Yunpeng Zuo ; Long Wu ; Qin Li ; Zhicheng Lu ; XueCai Tan ; Heyou Han
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：August 16, 2016
• 年：2016
• 卷：88
• 期：16
• 页码：8179-8187
• 全文大小：665K
• 年卷期：0
• ISSN：1520-6882

文摘

Dual-signaling ratiometric electrochemiluminescence (ECL) technology has attracted particular attention in analytical science due to its precise measurement to normalize variation in environmental changes. Creating new mated ECL report units with two emitting states and improving the detection sensitivity are major challenges for ratiometric ECL measurement. Here, we fabricate an ultrasensitive near-infrared ratiometric ECL aptasensor based on a dual-potential signal amplification strategy triggered by the quencher/enhancer [graphene/hemin/gold nanorods/G-quadruplex–hemin (rGO–H–AuNRs–G₄H) composite]. The composite was initially prepared through three consecutive steps: the π–π stacking interaction between hemin and graphene, in-site growth of AuNRs, and surface ligand exchange. Dual ECL quenching of quantum dots (QDs) and multiple signal enhancement of luminol can be achieved simultaneously by the fabrication of the sandwich “thrombin aptamer I (TBA₁)–TB–TBA₂ (rGO–H–AuNRs–G₄H)” mode: (i) the formation of three-dimensional G-quadruplex between aptamer and thrombin not only shortens the distance between the donor (QDs) and receptor (rGO–H and AuNRs) to trigger electrochemiluminescence energy transfer but also provides the place for intercalating hemin; (ii) the hemin intercalated into G₄ structure and hemin connected onto rGO together with AuNRs/rGO nanomaterials can achieve the multiple peroxidase-like catalysis of H₂O₂ to greatly enhance the ECL of luminol. The ratiometric ECL aptasensor self-calibrated by the internal reference (luminol or QDs) exhibits ultrasensitive and accurate analytical performance toward thrombin (TB) with a linear detection range from 100 ng/mL to 0.5 pg/mL and a detection limit of 4.2 fg/mL [defined as signal-to-noise ratio (S/N) = 3].