Li Yusi, Li Xia, Yang Fang, Yuan Ruo, Xiang Yun
Key Laboratory of Luminescence Analysis and Molecular Sensing, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Analyst. 2021 Mar 7;146(5):1590-1595. doi: 10.1039/d0an02288h. Epub 2021 Jan 18.
It is of great importance to develop biosensing methods for the sensitive and selective analysis of biomarkers at very low levels in biological samples. Using a new target-induced activation of the DNA polymerase activity for recycling amplification cascades, we describe an aptamer-based method for highly sensitive detection of platelet-derived growth factor BB (PDGF-BB) in human serums. The polymerase activity is initially inhibited by the binding of the polymerase to the enzyme aptamer sequence. PDGF-BB associates with and switches a PDGF-BB binding aptamer to trigger the release of an active polymerase, which further initiates the simultaneous recycling of the target PDGF-BB molecules and the enzyme aptamer sequence for the subsequent displacement of the fluorescently quenched probes to recover the fluorescence. Due to two recycling cascades, substantial fluorescence magnification is obtained for the highly sensitive detection of PDGF-BB with a low detection limit of 5.1 pM. Moreover, the potential applicability of this method for real samples was verified by determining PDGF-BB in diluted human serums, relying on the excellent specificity and selectivity of the aptamer. The demonstration of the PDGF-BB assay method here thus can be expanded for the construction of diverse sensing platforms for detecting different trace biomarkers with the integration of an elaborate design of the aptamer probes.
开发用于生物样品中极低水平生物标志物的灵敏且选择性分析的生物传感方法至关重要。利用一种新的靶标诱导的DNA聚合酶活性激活以进行循环扩增级联反应，我们描述了一种基于适体的方法，用于高灵敏检测人血清中的血小板衍生生长因子BB（PDGF-BB）。聚合酶活性最初因聚合酶与酶适体序列的结合而受到抑制。PDGF-BB与PDGF-BB结合适体结合并使其转换，从而触发活性聚合酶的释放，活性聚合酶进一步启动靶标PDGF-BB分子和酶适体序列的同时循环，以随后置换荧光猝灭探针来恢复荧光。由于两个循环级联反应，实现了显著的荧光放大，从而能够以5.1 pM的低检测限对PDGF-BB进行高灵敏检测。此外，依靠适体出色的特异性和选择性，通过测定稀释人血清中的PDGF-BB，验证了该方法对实际样品的潜在适用性。因此，这里的PDGF-BB检测方法的展示可以扩展到构建各种传感平台，通过精心设计适体探针来检测不同的痕量生物标志物。
