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目的:筛选血管炎性标志物脂蛋白相关磷脂酶A2（Lp-PLA2）的DNA适体，并建立以非标记核酸适体-纳米金为探针的可视化检测方法。方法:方法学建立。通过磁珠固定SELEX技术经孵育结合、ssDNA分离、PCR扩增、单链回收的8轮循环筛选Lp-PLA2适体，利用表面等离子体共振技术和流式细胞术验证适体的亲和力和特异性，并通过计算机软件模拟适体二级结构及其与靶蛋白的三维分子对接。随后制备适体-纳米金复合物，利用靶标竞争结合导致纳米金溶液在盐诱导下凝聚引起颜色变化，分光光度计检测溶液的吸光度检测靶标浓度，建立样品溶液中Lp-PLA2浓度与吸光度的线性关系。结果:筛选获得3条高亲和力、强特异性的Lp-PLA2核酸适体B76-2、B76-4及B76-5，解离常数分别为1.07、1.26及1.75 nmol/L；并成功基于B76-2适体构建纳米金比色传感方法，其线性范围和检测限分别是20~500 ng/ml和78 ng/ml，反应时间30 min，可特异性区分靶标与其他血栓标志物如凝血酶和髓过氧化物酶。结论:利用核酸适体-纳米金显色实现了简单、快速、特异的Lp-PLA2可视化检测。

Objective:The DNA aptamers of lipoprotein-associated phospholipase A2 (Lp-PLA2), a marker of vasculitis, were screened and a visual detection method using unlabeled nucleic acid aptamer-gold nanoparticle (AuNP) probe was established.Method:Lp-PLA2 aptamers were screened through 8 cycles of incubation binding, ssDNA isolation, PCR amplification and single strand recovery by the magnetic bead fixation SELEX technique. The affinity and specificity of the aptamers were validated using surface plasmon resonance technology and flow cytometry, and the secondary structure of the aptamer and its three-dimensional molecular docking with the target protein were simulated by computer software. Subsequently, aptamer-AuNP complex was prepared, and the color change was caused by salt-induced condensation of the AuNP solution by target competitive binding. Then, the target concentration was detected by measuring the absorbance of the solution with a spectrophotometer. The linear relationship between the sample absorbance and concentration of Lp-PLA2 were established under the optimal determine conditions.Results:Three Lp-PLA2 aptamers B76-2, B76-4 and B76-5 with high affinity and strong specificity were obtained, and the dissociation constants were 1.07, 1.26 and 1.75 nmol/L, respectively. Then AuNP colorimetric sensing method based on B76-2 aptamer was successfully constructed. The linear range and detection limit of Lp-PLA2 were 20-500 ng/ml and 78 ng/ml, respectively, and the reaction time was 30 min, which could specifically distinguish the target from other thrombotic markers such as thrombin and myeloperoxidase.Conclusion:A simple, rapid and specific visual detection method for visually detecting Lp-PLA2 was established by using aptamer-AuNP colorimetric assay.