Highly Selective Detection of K<sup>+</sup> Based on a Dimerized G-Quadruplex DNAzyme
Yu Cheng, Mingpan Cheng, Jingya Hao, Wenhui Miao, Wenqin Zhou, Guoqing Jia, Can Li
Abstract
High Resolution Image Download MS PowerPoint Slide Potassium ion (K + ) plays a crucial role in biological systems, such as maintaining cellular processes and causing diseases. However, specifically, the detection of K + is extremely challenging because of the coexistence of the chemically similar ion of Na + under physiological conditions. In this work, a K + specific biosensor is constructed on the basis of a dimerized G-quadruplex (GQ) DNA, which is promoted by K +, and the enzymatic activity of the resulting DNAzyme depends on the concentration of the K + . The K + in a 1–200 mM concentration range can be selectively detected by visual color, UV–Vis absorbance or fluorescence even if the concentration of the accompanying Na + is up to 140 mM at an ambient condition up to 45 °C. In addition, this system can also be used to selectively detect NH 4 + in a 5–200 mM concentration range. This dimerized DNAzyme offers a new type of biosensor with a potential application in the biological system.