Cardiac troponin I (CTnI) is demonstrated as one of the most promising disease biomarkers for early diagnosing acute myocardial infarction (AMI). To date, electrochemical immunosensors have been extensively studied in the field of cTnI determination. But highly accurate and sensitive cTnI detection by this method is still a challenge due to non-specific adsorption on electrode interfaces in complex human serum. As a result, it is necessary to develop an antifouling electrochemical immunosensor with high sensitivity for the detection of cTnI. In this work, an antifouling electrochemical immunosensor was constructed based on vertically-aligned peptide layer consisting of Au nanoparticles (AuNPs) and amphiphilic CEAK16 peptide (CEAK16@AuNPs) for sensitive and accurate detection of cTnI in human serum. The vertically-aligned CEAK16@AuNPs interface provided a stable hydration layer originated from attraction of water molecules by amino acids on the hydrophilic side of the CEAK16, which effectively reduced non-specific adsorption and enhanced electron transfer rate. The cTnI immunosensor possessed great analytical performance with a wide range from 1 fg mL to 1 μg mL and a low detection limit of 0.28 fg mL (S/N = 3). Additionally, the proposed CEAK16@AuNPs sensing interface showed excellent long-term antifouling performance and electrochemical activity that preserved 80 % of the initial signal after 20-days exposure in human serum samples. Consequently, the cTnI immunosensor displayed excellent detection accuracy compared to clinical methods and owned good selectivity, stability and reproducibility. The development of this strategy provides a versatile tool for accurate quantitative cTnI analysis in real human serum, thus helping to achieve early AMI diagnosis effectively and holding the promising potentials for other immunosensor in disease diagnosis.

中文翻译：

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基于垂直排列肽层的无污染电化学策略用于人血清中心肌肌钙蛋白 I 灵敏检测


心肌肌钙蛋白 I (CTnI) 被证明是早期诊断急性心肌梗死 (AMI) 最有前途的疾病生物标志物之一。迄今为止，电化学免疫传感器在 cTnI 测定领域已得到广泛研究。但由于复杂人血清中电极界面的非特异性吸附，该方法的高精度和灵敏 cTnI 检测仍然是一个挑战。因此，有必要开发一种高灵敏度的防污电化学免疫传感器来检测cTnI。在这项工作中，基于由金纳米粒子（AuNPs）和两亲性CEAK16肽（CEAK16@AuNPs）组成的垂直排列肽层构建了一种防污电化学免疫传感器，用于灵敏准确地检测人血清中的cTnI。垂直排列的CEAK16@AuNPs界面通过CEAK16亲水侧的氨基酸对水分子的吸引力提供了稳定的水化层，有效减少了非特异性吸附并提高了电子传输速率。 cTnI 免疫传感器具有出色的分析性能，分析范围从 1 fg mL 到 1 μg mL，检测限低至 0.28 fg mL（S/N = 3）。此外，所提出的 CEAK16@AuNPs 传感界面表现出优异的长期防污性能和电化学活性，在人血清样品中暴露 20 天后仍保留 80% 的初始信号。因此，与临床方法相比，cTnI免疫传感器表现出优异的检测精度，并具有良好的选择性、稳定性和重现性。 该策略的开发为真实人血清中准确定量cTnI分析提供了一种通用工具，从而有助于有效实现AMI早期诊断，并为其他免疫传感器在疾病诊断中的应用前景提供了广阔的前景。