Yang Liyuan, Fu Cuicui, Wang Hailong, Xu Shuping, Xu Weiqing
State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University, 2699 Qianjin Ave., Changchun, 130012, China.
Anal Bioanal Chem. 2017 Jan;409(1):235-242. doi: 10.1007/s00216-016-9992-z. Epub 2016 Oct 28.
A supramolecular recognition and oriented assembly system was developed on chip for the highly selective surface-enhanced Raman scattering (SERS) detection of thrombin by means of the aptamer-based SERS tag method. A 15-base thrombin-binding aptamer (TBA) with a thiol end was first immobilized on an Ag nanoprism array by the S-Ag bond. This aptamer has high binding affinity with thrombin when it folds into a G-quadruplex structure. After the recognition between the aptamer and thrombin, a bridge is built between the SERS tag (4-mercaptobenzoic acid marked Ag nanoparticle) and the fixed thrombin based on the activation of the carboxylic group of 4-mercaptobenzoic acid. Thus, the quantitative detection of thrombin can be achieved based on the SERS intensity of the immobilized SERS tags. The obvious advantages of this sensing method are as follows: (1) remarkable SERS enhancement due to the high electric field coupling effect via the gap structure formation, which improves the sensitivity of the SERS detection and the limit of detection of this method arrives in 1.6 × 10 M, (2) high selectivity based on the specific aptamer recognition toward thrombin, which can be extended to other enzymes easily by changing a proper sequence, (3) high repeatability of SERS signals according to a highly ordered structure, and (4) highly efficient oriented assembly of a sandwich structure over an Ag nanoprism array. The proposed method is expected to be a practical implement in medical diagnosis. Graphical Abstract Illustration of the aptamer-based SERS sensor for thrombin detection.
基于适体的表面增强拉曼散射（SERS）标签法，在芯片上开发了一种超分子识别和定向组装系统，用于凝血酶的高选择性表面增强拉曼散射检测。首先通过S-Ag键将带有巯基末端的15个碱基的凝血酶结合适体（TBA）固定在银纳米棱柱状阵列上。当该适体折叠成G-四链体结构时，它与凝血酶具有高结合亲和力。适体与凝血酶识别后，基于4-巯基苯甲酸羧基的活化，在SERS标签（4-巯基苯甲酸标记的银纳米颗粒）和固定的凝血酶之间构建一座桥梁。因此，基于固定化SERS标签的SERS强度可实现凝血酶的定量检测。这种传感方法的明显优点如下：（1）由于通过形成间隙结构产生高电场耦合效应，具有显著的SERS增强，提高了SERS检测的灵敏度，该方法的检测限达到1.6×10⁻¹¹M；（2）基于适体对凝血酶的特异性识别具有高选择性，通过改变适当的序列可轻松扩展到其他酶；（3）根据高度有序的结构，SERS信号具有高重复性；（4）在银纳米棱柱状阵列上高效定向组装三明治结构。该方法有望成为医学诊断中的一种实用工具。图摘要基于适体的凝血酶检测SERS传感器示意图。
