Abstract A highly sensitive and label-free fluorescence carcinoembryonic antigen (CEA) biosensor was developed via the target-triggered enzymatic recycling amplification reaction. To design this strategy, aggregation induced emission fluorogen (AIEgen) TPE-M was chosen as a signal reporter to enhance the detection efficiency, and L-cysteine (L-Cys) was utilized as a reactant to control over the fluorescence intensity due to its distinct capability of reacting with TPE-M and hemin/G-quadruplex. CEA triggered the in-situ generation of abundant hemin/G-quadruplex through polymerase/nicking enzyme-assisted recycling amplification, and the generated hemin/G-quadruplex could catalyze destruction of L-Cys. With L-Cys consuming, a significant decrease in fluorescence intensity was observed, demonstrating that the fluorescence intensity was indirectly relied on the CEA amount. As a consequence, a facile, precise and sensitive strategy for CEA assay was readily realized. Furthermore, the detection limit was 0.033 fmol/L (S/N = 3). The developed AIEgen-based biosensor provided a new method for the sensitive and reliable detection of CEA in biological liquids, thus displaying a significant promise for the CEA-related disease diagnosis.

中文翻译：

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用于高灵敏度检测癌胚抗原的基于聚集诱导发射荧光剂的无标记生物传感器

摘要 通过靶标触发的酶促循环扩增反应，研制了一种高灵敏度、无标记的荧光癌胚抗原（CEA）生物传感器。为了设计该策略，选择聚集诱导发射荧光 (AIEgen) TPE-M 作为信号报告基因以提高检测效率，并利用 L-半胱氨酸 (L-Cys) 作为反应物来控制荧光强度，因为它具有与 TPE-M 和氯化血红素/G-四链体反应的独特能力。CEA通过聚合酶/切口酶辅助循环扩增触发原位生成丰富的氯化血红素/G-四链体，生成的氯化血红素/G-四链体可催化L-Cys的破坏。随着 L-Cys 的消耗，观察到荧光强度显着降低，表明荧光强度间接依赖于 CEA 的量。因此，很容易实现了一种简便、精确和灵敏的 CEA 测定策略。此外，检测限为 0.033 fmol/L (S/N = 3)。开发的基于 AIEgen 的生物传感器为灵敏可靠地检测生物液体中的 CEA 提供了一种新方法，从而为 CEA 相关疾病的诊断显示出重要的前景。