title: Label-free G-quadruplex-specific fluorescent probe for sensitive detection of copper(II) ion.
abstract: An effective G-quadruplex-based probe has been constructed for rapid and sensitive detection of Cu(2+). In this probe, an anionic porphyrin, protoporphyrin IX (PPIX) served as a reference signal, which binds to G-quadruplex specifically and the fluorescence intensity increases sharply. While, in the presence of Cu(2+), the G-quadruplex can catalyze the related Cu(2+) insertion into the protoporphyrin, the fluorescent intensity is decreased. The fluorescence of the response ligand could be selectively quenched in the presence of Cu(2+) and not interfered by other metal ions. The probe provided an effective platform for reliable detection of Cu(2+) with a detection limit as low as 3.0nM, the high sensitivity was attributed to the strong metalation of PPIX with Cu(2+) catalyzed by G-quadruplex (PS5.M). Linear correlations were obtained over the logarithm of copper ion concentration in the range from 8×10(-9)M to 2×10(-6)M (R=0.998). The G-quadruplex-based probe also could be used to detect Cu(2+) in real water samples. Additionally, these striking properties endow the G-quadruplex-ligand with a great promise for analytical applications.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, PR China.
authors.forename: Libing
authors.initials: L
authors.lastname: Zhang
authors.forename: Jinbo
authors.initials: J
authors.lastname: Zhu
authors.forename: Jun
authors.initials: J
authors.lastname: Ai
authors.forename: Zhixue
authors.initials: Z
authors.lastname: Zhou
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Jia
authors.forename: Erkang
authors.initials: E
authors.lastname: Wang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002413:Cations, Divalent / Q000032:analysis; D003300:Copper / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D005618:Fresh Water / Q000032:analysis*; D054856:G-Quadruplexes; D057230:Limit of Detection; D009841:Oligonucleotides / Q000737:chemistry; D012722:Sewage / Q000032:analysis; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D002413:Cations, Divalent; D005456:Fluorescent Dyes; D009841:Oligonucleotides; D012722:Sewage; D003300:Copper