Cardiac troponin I (cTnI) as a biomarker of acute myocardial infarction (AMI) is directly related to myocardial damage. Here, we proposed a ratiometric aptamer-sensor (aptasensor) for quantifying cTnI based on surface-enhanced Raman scattering (SERS), in which the uniform and high-density gold array was decorated with highly specific aptamer Tro4 to form the capture substrate for target cTnI. Firstly, gold array was labeled with 5, 5’-dithio bis-(2-nitrobenzoic acid) (DTNB) as one SERS signal to effectively realize signal self-calibration. In addition, aptamer Tro6 targeting cTnI and 4-mercaptobenzoic acid (4-MBA) as another SERS signal were anchored to porous gold (pAu) to form a pAu signal probe. In the presence of cTnI, the capture substrate and pAu signal probes could build a typical sandwich structure, thus the ratio of SERS peak intensity (I/I) could be used to quantify cTnI. The ratiometric aptasensor showed a good linearity from 0.001 to 100 ng mL and a low detection limit down to 0.27 pg mL. Own to dual signal output and the gold array substrate, the aptasensor exhibited good reproducibility, high sensitivity and accuracy. When the aptasensor was applied to the quantification of cTnI in human serum samples, the detection performance was comparable to that of enzyme-linked immunosorbent assay (ELISA), proving that the sensor has a good prospect in the diagnosis of AMI disease.

中文翻译：

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一种基于 SERS 的新型比例适体传感器，用于准确定量心肌肌钙蛋白 I

心肌肌钙蛋白 I (cTnI) 作为急性心肌梗死 (AMI) 的生物标志物，与心肌损伤直接相关。在这里，我们提出了一种基于表面增强拉曼散射（SERS）定量cTnI的比率适体传感器（aptasensor），其中均匀且高密度的金阵列用高度特异性的适体Tro4装饰以形成目标的捕获底物肌钙蛋白I。首先，用5, 5'-二硫代双（2-硝基苯甲酸）（DTNB）标记金阵列作为一个SERS信号，有效实现信号自校准。此外，将 cTnI 和 4-巯基苯甲酸 (4-MBA) 作为另一种 SERS 信号的适体 Tro6 锚定到多孔金 (pAu) 上，形成 pAu 信号探针。在 cTnI 存在的情况下，捕获底物和 pAu 信号探针可以构建典型的三明治结构，因此 SERS 峰强度比 (I/I) 可用于量化 cTnI。比例适体传感器在 0.001 至 100 ng mL 范围内表现出良好的线性，检测限低至 0.27 pg mL。由于双信号输出和金阵列基板，适配体传感器表现出良好的重现性、高灵敏度和准确性。当该适配体传感器应用于人血清样本中cTnI的定量时，检测性能与酶联免疫吸附测定（ELISA）相当，证明该传感器在AMI疾病的诊断中具有良好的前景。