背景:心肌肌钙蛋白I(CTnI)被证明是早期诊断急性心肌梗死(AMI)最有希望的疾病生物标志物之一。迄今为止,电化学免疫传感器在cTnI测定领域已被广泛研究。但是,由于在复杂的人血清中电极界面上的非特异性吸附,因此通过该方法进行的高度准确和灵敏的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。
结果:在这项工作中,基于由Au纳米颗粒(AuNPs)和两亲性CEAK16肽(CEAK16@AuNPs)组成的垂直排列的肽层,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@AuNP界面提供了一个稳定的水合层,该水合层源于CEAK16亲水侧氨基酸对水分子的吸引,从而有效地减少了非特异性吸附并提高了电子转移速率。cTnI免疫传感器具有良好的分析性能,范围从1fgmL-1到1μgmL-1,检测限低至0.28fgmL-1(S/N=3)。此外,拟议的CEAK16@AuNPs传感界面显示出优异的长期防污性能和电化学活性,在暴露于人血清样品20天后保留了80%的初始信号。因此,与临床方法相比,cTnI免疫传感器显示出优异的检测精度,具有良好的选择性,稳定性和重现性。
结论:该策略的开发为真实人血清中的cTnI准确定量分析提供了通用工具,从而有助于有效地实现AMI的早期诊断,并具有其他免疫传感器在疾病诊断中的潜力。
BACKGROUND: 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.
RESULTS: 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-1 to 1 μg mL-1 and a low detection limit of 0.28 fg mL-1 (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.
CONCLUSIONS: 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.