Jing Wenwen, Wang Yi, Chen Chao, Zhang Fenni, Yang Yunze, Ma Guangzhong, Yang Eric H, Snozek Christine L N, Tao Nongjian, Wang Shaopeng
Center for Biosensors and Bioelectronics, The Biodesign Institute, Arizona State University, Tempe, Arizona 85287, United States.
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
ACS Sens. 2021 Feb 26;6(2):399-407. doi: 10.1021/acssensors.0c01681. Epub 2020 Oct 9.
Rapid and sensitive detection of biomarkers is the key to the diagnosis of acute diseases. One example is the detection of troponin in myocardial infarction. Here, we report a gradient-based digital immunoassay method, which can achieve high-sensitivity cardiac troponin T (hs-cTnT) detection with only 1 μL of plasma sample. We designed a multizone microfluidic channel functionalized with capture antibody specific to troponin. Taking advantage of limited sample volume, a troponin concentration gradient is created along the channel because of binding induced depletion. We quantified the concentration gradient by counting the detection antibody conjugated gold nanoparticles bound to different test zones with optical imaging. Differential counting between the zones removes most common noises and nonspecific bindings. The total analytical time is about 30 min, and the limit of quantification is 6.2 ng/L. We examined 41 clinical plasma samples from 15 patients and the change in hs-cTnT concentration in serial samples showed good linear correlation with clinical results ( = 0.98). Therefore, this simple and sensitive gradient-based digital immunoassay method is a promising technology for clinical hs-cTnT detection and could be adapted for detection of other biomarkers.
生物标志物的快速灵敏检测是急性疾病诊断的关键。一个例子是心肌梗死中肌钙蛋白的检测。在此，我们报告一种基于梯度的数字免疫分析方法，该方法仅用1 μL血浆样本就能实现高灵敏度心肌肌钙蛋白T（hs-cTnT）检测。我们设计了一种多区域微流控通道，用针对肌钙蛋白的捕获抗体进行功能化修饰。利用有限的样本体积，由于结合诱导耗尽，沿着通道形成了肌钙蛋白浓度梯度。我们通过光学成像对结合到不同测试区域的检测抗体偶联金纳米颗粒进行计数来量化浓度梯度。区域间的差异计数消除了大多数常见噪声和非特异性结合。总分析时间约为30分钟，定量限为6.2 ng/L。我们检测了来自15名患者的41份临床血浆样本，系列样本中hs-cTnT浓度的变化与临床结果显示出良好的线性相关性（ = 0.98）。因此，这种基于梯度的简单灵敏数字免疫分析方法是一种用于临床hs-cTnT检测的有前景的技术，并且可适用于其他生物标志物的检测。
