title: Electrocatalytic assay of mercury(II) ions using a bifunctional oligonucleotide signal probe.
abstract: Engineered nucleic acid probes containing recognition and signaling functions find growing interest in biosensor design. In this paper, we developed a novel electrochemical biosensor for sensitive and selective detecting of Hg(2+) based on a bifunctional oligonucleotide signal probe combining a mercury-specific sequence and a G-quadruplex (G4) sequence. For constructing the electrochemical Hg(2+) biosensor, a thiolated, mercury-specific oligonucleotide capture probe was first immobilized on gold electrode surface. In the presence of Hg(2+), a bifunctional oligonucleotide signal probe was hybridized with the immobilized capture probe through thymine-mercury(II)-thymine interaction-mediated surface hybridization. The further interaction between G4 sequence of the signal probe and hemin generated a G4-hemin complex, which catalyzed the electrochemical reduction of hydrogen peroxide, producing amplified readout signals for Hg(2+) interaction events. This electrochemical Hg(2+) biosensor was highly sensitive and selective to Hg(2+) in the concentration of 1.0 nM to 1 μM with a detection limit of 0.5 nM. The new design of bifunctional oligonucleotide signal probes also provides a potential alternative for developing simple and effective electrochemical biosensors capable of detecting other metal ions specific to natural or artificial bases.
authors: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, China.
authors: Ziping
authors: Z
authors: Zhang
authors: Jungang
authors: J
authors: Yin
authors: Zhaoyang
authors: Z
authors: Wu
authors: Ruqin
authors: R
authors: Yu
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004563:Electrochemistry; D004566:Electrodes; D054856:G-Quadruplexes; D006046:Gold / Q000737:chemistry; D006427:Hemin / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D008958:Models, Molecular; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes / Q000737:chemistry*; D010084:Oxidation-Reduction; D013941:Thymine / Q000737:chemistry
chemical_list: D015345:Oligonucleotide Probes; D006427:Hemin; D006046:Gold; D006861:Hydrogen Peroxide; D008628:Mercury; D013941:Thymine