Rapid and multiplexed detection of biomarkers plays an indispensable role in disease diagnosis. Although paper-based lateral flow immunoassays have been widely used in this field, the speediness and throughput are still challenging issues. Herein, an electrochemical vertical flow immunoassay device (eVFID) is fabricated for rapid, ultrasensitive, and multiplexed detection of inflammatory biomarkers. Working electrodes with excellent electrochemical performance and permeability properties were directly fabricated on the nitrocellulose membrane to enable both the vertical flow of the sample solution and electrochemical detection. This vertical configuration can remarkably improve the speediness of the immunoassay and effectively inhibit the cross-talk reactions among immunomolecules, thus allowing rapid and simultaneous detection of multiplexed biomarkers. Furthermore, a signal amplification strategy based on horseradish peroxidase and tetramethylbenzidine was integrated into the eVFID to substantially increase the sensitivity of the electrochemical detection. A low limit of detection of 0.1 and 0.22 pg mL^–1 was obtained for two low-abundance inflammatory biomarkers, interleukin-6 (IL-6) and procalcitonin (PCT), respectively. Finally, using a two-channel eVFID, simultaneous detection of IL-6 and PCT in human plasma samples was successfully realized within 5 min. We believe that the eVFID holds great promise for speedy and high-throughput biomarker detection at the point of care.

中文翻译：

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用于快速同时检测白细胞介素 6 和降钙素原的超灵敏电化学垂直流免疫测定


生物标志物的快速和多重检测在疾病诊断中起着不可或缺的作用。尽管基于纸张的侧向层析免疫测定已在该领域得到广泛应用，但速度和通量仍然是具有挑战性的问题。在此，制造了一种电化学垂直流免疫测定装置 （eVFID），用于快速、超灵敏和多路复用检测炎症生物标志物。直接在硝酸纤维素膜上制备具有优异电化学性能和渗透性的工作电极，以实现样品溶液的垂直流动和电化学检测。这种垂直配置可以显著提高免疫测定的速度，并有效抑制免疫分子之间的串扰反应，从而允许快速、同时检测多重生物标志物。此外，将基于辣根过氧化物酶和四甲基联苯胺的信号放大策略集成到 eVFID 中，以显着提高电化学检测的灵敏度。两种低丰度炎症生物标志物白细胞介素-6 （IL-6） 和降钙素原 （PCT） 的检测下限分别为 0.1 和 0.22 pg ^mL-1。最后，使用双通道 eVFID，在 5 分钟内成功实现了人血浆样品中 IL-6 和 PCT 的同时检测。我们相信 eVFID 在护理点快速和高通量生物标志物检测方面前景广阔。