Xue Yunpeng, Shi Ruyu, Chen Liangyu, Ju Shaowei, Yan Tianhang, Tan Xin, Hou Lijie, Jin Lihong, Shen Bingjun
Department of Biomedical Engineering, Changchun University of Science and Technology, Changchun 130022, China.
Department of Bioengineering, Changchun University of Science and Technology, Changchun 130022, China.
Langmuir. 2024 Dec 24;40(51):26988-26996. doi: 10.1021/acs.langmuir.4c03411. Epub 2024 Dec 11.
Cardiac troponin I (cTnI) is a highly sensitive and important serological marker for clinical diagnosis of myocardial injury. Its rapid detection is crucial for the early diagnosis of cardiovascular diseases such as acute myocardial infarction. In this study, based on nucleic acid molecular hybridization and aptamer-specific binding to target molecules, a label-free liquid crystal aptamer sensor based on single-stranded nucleic acid π-structures was developed and applied for the quantitative detection of cTnI. The CP1 and CP2 oligonucleotide chains, complementary to the bases at both ends of the aptamer, are covalently bonded to the sensor substrate via APTES and GA-mediated molecules. The aptamer forms a π-structure with CP1 and CP2 through nucleic acid hybridization, serving as a target molecule capture probe. When cTnI is present in the system, cTnI and the complementary oligonucleotide chains competitively bind with the aptamer, causing the breakdown of the π-structure within the sensor. This reinstates the long-range ordered alignment of the 5CB liquid crystal molecules within the sensor, enabling quantitative measurement of cTnI through variations in optical images. Experimental results show that within the range of 0.01 to 25 ng/mL for cTnI concentration, there is a linear correlation between the brightness area coverage (Br) in the polarized light microscopy images of the sensor and the logarithm of the cTnI concentration, with a correlation coefficient (). The detection limit is 5.16 pg/mL. This method is label-free, simple to operate, and low-cost, with good specificity and a low detection limit, achieving cTnI detection in serum samples.
心肌肌钙蛋白I（cTnI）是用于心肌损伤临床诊断的一种高度敏感且重要的血清学标志物。其快速检测对于急性心肌梗死等心血管疾病的早期诊断至关重要。在本研究中，基于核酸分子杂交和适配体与靶分子的特异性结合，开发了一种基于单链核酸π结构的无标记液晶适配体传感器，并将其应用于cTnI的定量检测。与适配体两端碱基互补的CP1和CP2寡核苷酸链通过APTES和GA介导的分子共价连接到传感器基底上。适配体通过核酸杂交与CP1和CP2形成π结构，作为靶分子捕获探针。当系统中存在cTnI时，cTnI与互补寡核苷酸链竞争结合适配体，导致传感器内π结构的破坏。这恢复了传感器内5CB液晶分子的长程有序排列，从而能够通过光学图像的变化对cTnI进行定量测量。实验结果表明，在cTnI浓度为0.01至25 ng/mL的范围内，传感器偏光显微镜图像中的亮度面积覆盖率（Br）与cTnI浓度的对数之间存在线性相关性，相关系数为（）。检测限为5.16 pg/mL。该方法无标记、操作简单、成本低，具有良好的特异性和低检测限，可实现血清样本中cTnI的检测。
