title: Potassium-sensitive G-quadruplex DNA for sensitive visible potassium detection.
abstract: A novel visual method for K(+) detection is developed utilizing a K(+)-sensitive G-quadruplex DNA named PS5.M as the sensing element. In the absence of K(+), PS5.M is in a random coil state and does not bind hemin. Upon addition of K(+), PS5.M folds into the quadruplex structure stabilized by K(+). Such quadruplex structure is able to bind hemin to form the hemin-G-quadruplex DNAzyme that catalyzes the H(2)O(2)-mediated oxidation of colorless 3,3',5,5'-tetramethylbenzidine to the blue product. Under the optimal conditions, the color change can be clearly observed with the naked eye in the concentration range from 2 to 1000 microM. Through this facile approach, K(+) can be detected down to 2 microM, with high selectivity against other cations. In view of its simplicity, sensitivity and specificity, our developed visual method for K(+) detection would potentially be utilized for bioassays and K(+)-sensitive test paper.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, PR China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Yang
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.forename: Bingling
authors.initials: B
authors.lastname: Li
authors.forename: Erkang
authors.initials: E
authors.lastname: Wang
mesh_terms: D001560:Benzidines / Q000737:chemistry; D003124:Colorimetry / Q000379:methods*; D021881:DNA, Catalytic / Q000737:chemistry* / Q000378:metabolism; D054856:G-Quadruplexes; D006427:Hemin / Q000737:chemistry / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry; D010084:Oxidation-Reduction; D011188:Potassium / Q000032:analysis*
chemical_list: D001560:Benzidines; D021881:DNA, Catalytic; C021758:3,3',5,5'-tetramethylbenzidine; D006427:Hemin; D006861:Hydrogen Peroxide; D011188:Potassium