DNA-Based Hybridization Chain Reaction for Amplified Bioelectronic Signal and Ultrasensitive Detection of Proteins
DNA-Based Hybridization Chain Reaction for Amplified Bioelectronic Signal and Ultrasensitive Detection of Proteins
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基于 DNA 的杂交链式反应，用于放大生物电子信号和超灵敏蛋白质检测
DOI：
10.1021/ac3009065
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发表时间：
2012-06-19
影响因子：
7.4
通讯作者：
Knopp, Dietmar
中科院分区：
文献类型：
--
作者：
Zhang, Bing;Liu, Bingqian;Knopp, Dietmar
本工作报告了一种新的电化学免疫分析方案，用于在超低浓度下使用基于DNA的杂交链反应（HCR）测定蛋白质（人IgG在这里用作模型目标分析物）的信号放大。免疫HCR检测由磁性免疫传感探针、与DNA起始链缀合的纳米金标记的信号探针和两种不同的发夹DNA分子组成。信号被发夹探针上标记的二茂铁放大。在目标IgG存在下，磁珠上的固定化抗体与金纳米颗粒上的信号抗体之间可形成夹心免疫复合物。所携带的DNA起始链按顺序打开发夹DNA结构，并在两个交替的发夹之间传播杂交事件的链式反应，以形成带切口的双螺旋。在相邻的探针上形成许多二茂铁分子，每个二茂铁分子在所施加的电势内产生电化学信号。在最佳条件下，免疫HCR测定法在低至0.1 fg mL（-1）的浓度下对目标IgG的测定呈现出良好的电化学响应。重要的是，该方法可以进一步扩展到其他蛋白质或生物标志物的检测。
This work reports a novel electrochemical immunoassay protocol with signal amplification for determination of proteins (human IgG here used as a model target analyte) at an ultralow concentration using DNA-based hybridization chain reaction (HCR). The immuno-HCR assay consists of magnetic immunosensing probes, nanogold-labeled signal probes conjugated with the DNA initiator strands, and two different hairpin DNA molecules. The signal is amplified by the labeled ferrocene on the hairpin probes. In the presence of target IgG, the sandwiched immunocomplex can be formed between the immobilized antibodies on the magnetic beads and the signal antibodies on the gold nanoparticles. The carried DNA initiator strands open the hairpin DNA structures in sequence and propagate a chain reaction of hybridization events between two alternating hairpins to form a nicked double-helix. Numerous ferrocene molecules are formed on the neighboring probe, each of which produces an electrochemical signal within the applied potentials. Under optimal conditions, the immuno-HCR assay presents good electrochemical responses for determination of target IgG at a concentration as low as 0.1 fg mL(-1). Importantly, the methodology can be further extended to the detection of other proteins or biomarkers.