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An ultrasensitive enzyme-free electrochemical immunosensor based on redox cycling amplification using methylene blue
Analyst ( IF 3.6 ) Pub Date : 2017-08-09 00:00:00 , DOI: 10.1039/c7an00789b
Gorachand Dutta 1, 2, 3, 4 , Peter B. Lillehoj 1, 2, 3, 4, 5
Affiliation  

We report a new enzyme-free electrochemical sensor for ultrasensitive measurements of protein biomarkers in plasma and whole blood samples based on a unique electrochemical–chemical–chemical (ECC) redox cycling signal amplification scheme. This scheme uses methylene blue (MB) as a redox indicator which undergoes an endergonic reaction with Ru(NH3)63+ and a highly exergonic reaction with tris(2-carboxyethyl)phosphine (TCEP). This approach offers improved detection sensitivity and sensor stability compared with enzyme-based ECC redox cycling techniques, while involving a simpler sensor modification process and detection protocol. This redox cycling scheme was combined with a robust immunosandwich assay for quantitative measurements of protein biomarkers. For proof of principle, Plasmodium falciparum histidine-rich protein 2 (PfHRP2) was measured in human plasma and whole blood samples, which could be detected down to 10 fg mL−1 and 18 fg mL−1, respectively. Furthermore, this immunosensor exhibits high selectivity, excellent reproducibility and good stability for up to 2 weeks, making it a promising platform for point-of-care testing, especially for detecting extremely low biomarker concentrations in raw biofluids.

中文翻译:

基于亚甲基蓝氧化还原循环扩增的超灵敏无酶电化学免疫传感器

我们报告了一种新型的无酶电化学传感器,该传感器基于独特的电化学-化学-化学(ECC)氧化还原循环信号放大方案,可以超灵敏地测量血浆和全血样品中的蛋白质生物标志物。该方案使用亚甲基蓝(MB)作为氧化还原指示剂,它与Ru(NH 36 3+以及与三(2-羧乙基)膦(TCEP)的强力反应。与基于酶的ECC氧化还原循环技术相比,此方法可提供更高的检测灵敏度和传感器稳定性,同时涉及更简单的传感器修改过程和检测协议。该氧化还原循环方案与鲁棒的免疫夹心测定法相结合,用于蛋白质生物标志物的定量测量。为证明原理,在人血浆和全血样品中测定了恶性疟原虫组氨酸富集蛋白2(Pf HRP2),最低可检测到10 fg mL -1和18 fg mL -1, 分别。此外,这种免疫传感器具有长达2周的高选择性,出色的可重复性和良好的稳定性,使其成为即时检验的平台,尤其是用于检测原始生物流体中极低的生物标志物浓度的平台。
更新日期:2017-09-08
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