Highly sensitive fluorescent sensor for mercury ion based on photoinduced charge transfer between fluorophore and pi-stacked T-Hg(II)-T base pairs.
A novel and simple oligodeoxyribonucleotide-based sensor with single fluorophore-labeled for mercury ion sensing was reported. An oligodeoxyribonucleotide poly(dT) was labeled with fluorescein as donor. Based on the specific binding of Hg(II) to T-T mismatch base pairs, the formation of pi-stacked [T-Hg(II)-T] with "sandwich" structure on the addition of Hg(II) ions facilitates the electron transfer via photoinduced charge transfer (PCT), which creates an additional nonradiative decay channel for excited fluorophore and triggers the fluorescence to be quenched. The pi-stacked [T-Hg(II)-T] functioned not only as mercury ion recognition but also as an electron acceptor to quench the donor. A linear relationship was observed over the range of 0-1.0 microM with the detection limit of 20 nM for mercury ions. The fluorescence quenching phenomenon and quenching mechanism, reliability and selectivity of the system were investigated in detail.
Guo
Liangqia
L
Ministry of Education Key Laboratory of Analysis and Detection Technology for Food Safety (Fuzhou University), Fuzhou University, Fuzhou, Fujian, 350002, China.
Hu
Hong
H
Sun
Ruiqing
R
Chen
Guonan
G
D020029:Base Pairing; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D004579:Electron Transport; D008628:Mercury / Q000032:analysis*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000235:genetics; D055668:Photochemical Processes; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence; D013941:Thymine / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D009838:Oligodeoxyribonucleotides; D014867:Water; D008628:Mercury; D013941:Thymine