G-quadruplex DNAzyme-based electrochemiluminescence biosensing strategy for VEGF165 detection: Combination of aptamer-target recognition and T7 exonuclease-assisted cycling signal amplification
G-quadruplex DNAzyme-based electrochemiluminescence biosensing strategy for VEGF165 detection: Combination of aptamer-target recognition and T7 exonuclease-assisted cycling signal amplification
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基于 G-四链体 DNAzyme 的 VEGF165 检测电化学发光生物传感策略：适体-靶标识别和 T7 核酸外切酶辅助循环信号放大的组合
DOI：
10.1016/j.bios.2015.05.069
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发表时间：
2015-12-15
影响因子：
12.6
通讯作者：
Cai, Chenxin
中科院分区：
文献类型：
--
作者：
Zhang, Hui;Li, Meixing;Cai, Chenxin
血管内皮生长因子（VEGF）的表达与肿瘤的发生、发展密切相关。这项工作报告了一种电化学发光（ECL）方法，用于高灵敏度检测VEGF（165）。该方法包括核酸适体-靶标识别、T7核酸外切酶（17 Exo）辅助的循环信号放大和DNAzyme对CdS：Eu纳米晶体（NC）电化学发光的有效猝灭。以CdS：Eu纳米粒子为电化学发光底物，将富含鸟嘌呤（G）的单链DNA（ssDNA）序列和VEGF（165）适体共固定在CdS：Eu纳米粒子修饰玻碳电极表面。在识别并结合VEGF（165）后，适体从电极表面移开，并诱导T7 Exo对靶DNA的预期环状切割。在氯化血红素和K+存在下，CdS：Eu薄膜上释放出大量的富G单链DNA，并折叠成G-四链体/氯化血红素DNA酶，从而降低了CdS：Eu的电致发光强度。VEGF（165）在1 pM ~ 20 nM范围内线性关系良好，检测限为0.2 pM。该方法可作为一种通用的、有前途的检测多种生物标志物的方法，用于早期临床诊断。(C)2015 Elsevier B. V.版权所有。
The expression profile of vascular endothelial growth factor (VEGF) is highly correlated with the occurrence and development of cancer. This work reports an electrochemiluminescence (ECL) approach for highly sensitive detection of VEGF(165). This approach comprises aptamer-target recognition, T7 exonuclease (17 Exo)-assisted cycling signal amplification and efficient quenching of ECL of CdS:Eu nanocrystals (NCs) by using DNAzyme. In this assay, CdS:Eu NCs were used as the ECL substrate, A guanine (G)-rich single-stranded DNA (ssDNA) sequence and VEGF(165) aptamer were co-immobilized on the surface of the CdS:Eu NCs modified glassy carbon electrode. After recognition and binding to VEGF(165), the aptamer moved away from the electrode surface and induced the proposed cyclic cleavage of the target DNA with T7 Exo. A large amount of G-rich ssDNA was released on the CdS:Eu film and folded into G-quadruplex/hemin DNAzyme in the presence of hemin and K+, consequently decreasing the ECL intensity of CdS:Eu. A good linearity was obtained for VEGF(165) detection within the range of 1 pM to 20 nM with a detection limit of 0.2 pM. This assay could be a universal and promising protocol for detection of various biomarkers for early clinical diagnosis. (C) 2015 Elsevier B.V. All rights reserved.