title: Quantum dot-phenanthroline dyads: detection of double-stranded DNA using a photoinduced hole transfer mechanism.
abstract: We have developed a new fluorescent probe based on direct conjugation between 1,10-phenanthroline (Phen) and water-soluble thioglycolic acid (TGA) capped CdTe quantum dots (QDs) for the detection of double-stranded DNA (dsDNA). Phen could directly adsorb onto the QDs surface by metal-affinity driven coordination, quenching the photoluminescence (PL) of QDs via the photoinduced hole transfer process; addition of dsDNA would bring the restoration of QDs PL, as Phen could intercalate into dsDNA followed by its dissociation from the QDs surface. The dependence of QDs PL on the dsDNA amount as well as temperature was utilized to investigate the Phen-dsDNA interaction. The obtained binding constant of the QD-Phen dyad was 2-3 orders of magnitude higher than that of Phen-based metal complexes. Both the binding constant and the binding site of dsDNA with Phen increased with the elevated temperature, owing to an endothermic process. At 37 °C, sensitive detection of dsDNA with a detection limit of ~3 nmol L(-1) was achieved. Therefore, the QD-molecule direct conjugation based fluorescent probe could provide an effective alternative to those based on QD-bioconjugation and QD-ionic conjugation.
authors.affiliation: State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
authors.forename: Kao
authors.initials: K
authors.lastname: Zhu
authors.forename: Tao
authors.initials: T
authors.lastname: Ding
authors.forename: Xianyun
authors.initials: X
authors.lastname: Hu
authors.forename: Qingjiang
authors.initials: Q
authors.lastname: Sun
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Xu
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry; D004247:DNA / Q000032:analysis*; D007700:Kinetics; D008027:Light; D010618:Phenanthrolines / Q000737:chemistry*; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence; D013691:Tellurium / Q000737:chemistry; D013816:Thermodynamics; D013864:Thioglycolates / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D056831:Coordination Complexes; D010618:Phenanthrolines; D013864:Thioglycolates; C017487:2-mercaptoacetate; D004247:DNA; D013691:Tellurium; C028337:cadmium telluride; C025205:1,10-phenanthroline