The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, PR China; Public Health Research Center at Jiangnan University, Wuxi 214122, PR China.
The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, PR China.
Biosens Bioelectron. 2016 Jul 15;81:214-220. doi: 10.1016/j.bios.2016.02.038. Epub 2016 Feb 16.
Herein, we report a ratiometric fluorescence assay based on graphene quantum dots (GQDs) for the ultrasensitive DNA detection by coupling the nicking endonuclease assisted target recycling and the G-quadruplex/hemin DNAzyme biocatalysis for cascade signal amplifications. With o-phenylenediamine acted as the substrate of G-quadruplex/hemin DNAzyme, whose oxidization product (that is, 2,3-diaminophenazine, DAP) quenched the fluorescence intensity of GQDs (at 460nm) obviously, accompanied with the emergence of a new emission of DAP (at 564nm). The ratiometric signal variations at the emission wavelengths of 564 and 460nm (I564/I460) were utilized for label-free, sensitive, and selective detection of target DNA. Utilizing the nicking endonuclease assisted target recycling and the G-quadruplex/hemin DNAzyme biocatalysis for amplified cascade generation of DAP, the proposed bioassay exhibited high sensitivity toward target DNA with a detection limit of 30fM. The method also had additional advantages such as facile preparation and easy operation.
在此，我们报告了一种基于石墨烯量子点（GQDs）的比率荧光分析方法，用于通过连接切口内切酶辅助的靶标循环和 G-四链体/血红素 DNA 酶生物催化进行级联信号放大，来实现对 DNA 的超灵敏检测。邻苯二胺作为 G-四链体/血红素 DNA 酶的底物，其氧化产物（即 2,3-二氨基吩嗪，DAP）明显猝灭了 GQDs 的荧光强度（在 460nm 处），同时伴随着 DAP 的新发射（在 564nm 处）的出现。在发射波长为 564nm 和 460nm 处的比率信号变化（I564/I460）用于无标记、敏感和选择性检测靶 DNA。利用切口内切酶辅助的靶标循环和 G-四链体/血红素 DNA 酶生物催化放大 DAP 的级联生成，该生物分析方法对靶 DNA 具有高灵敏度，检测限为 30fM。该方法还具有易于制备和操作简便等优点。
