Park Yeonkyung, Lee Chang Yeol, Park Ki Soo, Park Hyun Gyu
Department of Chemical and Biomolecular, Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, 05029, Republic of Korea.
Chemistry. 2017 Dec 6;23(68):17379-17383. doi: 10.1002/chem.201704346. Epub 2017 Nov 14.
A new enzyme-free system for colorimetric Cu detection, which relies on target-triggered DNAzymes and toehold-mediated DNA strand-displacement circuits, is described. The system employs a DNAzyme designed to undergo self-cleavage in the presence of Cu and release a catalyst strand that triggers a sequential toehold-mediated strand displacement reaction. This event leads to the release of a split G-quadruplex DNAzyme strand that is initially caged and inactivated by a blocker strand. A fuel strand is further incorporated for the recycling of the catalyst strand to promote another toehold-mediated strand displacement event, which consequently produces a large number of active split G-quadruplex DNAzymes. By employing this design principle, target Cu was very successfully identified with a detection limit of 1.31 nm based on the distinct colorimetric signal developed by the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid promoted by the peroxidase mimicking activity of the released G-quadruplex DNAzymes. Finally, the practical capability of this sensing system was very successfully demonstrated by its use to reliably determine Cu in tap water.
本文描述了一种用于比色法检测铜的新型无酶系统，该系统依赖于目标触发的DNA酶和由链置换引发的DNA链置换回路。该系统采用了一种DNA酶，其设计目的是在铜存在的情况下进行自我切割，并释放出一条催化链，该催化链触发一系列由链置换引发的链置换反应。这一过程导致一条分裂的G-四链体DNA酶链被释放出来，该链最初被一条阻断链封闭并失活。此外，还引入了一条燃料链，用于催化链的循环利用，以促进另一次由链置换引发的链置换反应，从而产生大量有活性的分裂G-四链体DNA酶。通过采用这种设计原理，基于释放的G-四链体DNA酶的过氧化物酶模拟活性促进2,2'-联氮双(3-乙基苯并噻唑啉)-6-磺酸氧化产生的明显比色信号，成功地识别了目标铜，检测限为1.31 nm。最后，通过该传感系统用于可靠测定自来水中的铜，非常成功地证明了该传感系统的实际应用能力。
