title: A parallel G-quadruplex-selective luminescent probe for the detection of nanomolar calcium(II) ion.
abstract: A parallel G-quadruplex-selective iridium(III) complex has been synthesized and employed as a luminescent probe in a label-free G-quadruplex-based detection assay for Ca(2+) ions in aqueous solution. In this assay, a guanine-rich oligonucleotide (G4, 5'-G4T4G4-3') initially exists in an antiparallel G-quadruplex conformation, resulting in a low luminescence signal. Upon incubation with Ca(2+) ions, the antiparallel G-quadruplex is induced into a parallel G-quadruplex conformation, which greatly enhances the luminescence emission of the iridium(III) probe. This method was highly sensitive for Ca(2+) ions with a limit of detection in the nanomolar range, and was selective for Ca(2+) over other metal ions.
authors.affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
authors.forename: Hong-Zhang
authors.initials: HZ
authors.lastname: He
authors.forename: Modi
authors.initials: M
authors.lastname: Wang
authors.forename: Daniel Shiu-Hin
authors.initials: DS
authors.lastname: Chan
authors.forename: Chung-Hang
authors.initials: CH
authors.lastname: Leung
authors.forename: Xuexia
authors.initials: X
authors.lastname: Lin
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Lin
authors.forename: Dik-Lung
authors.initials: DL
authors.lastname: Ma
mesh_terms: D015374:Biosensing Techniques; D002118:Calcium / Q000032:analysis* / Q000737:chemistry; D056831:Coordination Complexes / Q000032:analysis / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry; D054856:G-Quadruplexes; D057230:Limit of Detection; D049408:Luminescent Agents / Q000737:chemistry; D008163:Luminescent Measurements; D011089:Polydeoxyribonucleotides / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D004277:DNA, Single-Stranded; D049408:Luminescent Agents; D011089:Polydeoxyribonucleotides; D004247:DNA; C427203:calf thymus DNA; D002118:Calcium
keywords: Ca(2+) ions; G-quadruplex; Iridium; Luminescence; Metal complex; calf-thymus DNA; ctDNA; double-stranded DNA; dsDNA; single-stranded DNA; ssDNA