title: Oligonucleotide probes applied for sensitive enzyme-amplified electrochemical assay of mercury(II) ions.
abstract: We developed a novel electrochemical sensor for Hg(2+) detection using two mercury-specific oligonucleotide probes and streptavidin-horseradish peroxidase (HRP) enzymatic signal amplification. The two mercury-specific oligonucleotide probes comprised a thiolated capture probe and a biotinated signal probe. The thiolated capture probe was immobilized on a gold electrode. In the presence of Hg(2+), the thymine-Hg(2+)-thymine (T-Hg(2+)-T) interaction between the mismatched T-T base pairs directed the biotinated signal probe hybridizing to the capture probe and yielded a biotin-functioned electrode surface. HRP was then immobilized on the biotin-modified substrate via biotin-streptavidin interaction. The immobilized HRP catalyzed the oxidation of hydroquinone (H(2)Q) to benzoquinone (BQ) by hydrogen peroxide (H(2)O(2)) and the generated BQ was further electrochemically reduced at the modified gold electrode, producing a readout signal for quantitative detection of Hg(2+). The results showed that the enzyme-amplified electrochemical sensor system was highly sensitive to Hg(2+) in the concentration of 0.5 nM to 1 μM with a detection limit of 0.3 nM, and it also demonstrated excellent selectivity against other interferential metal ions.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, China.
authors.forename: Ziping
authors.initials: Z
authors.lastname: Zhang
authors.forename: Aman
authors.initials: A
authors.lastname: Tang
authors.forename: Shuzhen
authors.initials: S
authors.lastname: Liao
authors.forename: Pengfei
authors.initials: P
authors.lastname: Chen
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Wu
authors.forename: Guoli
authors.initials: G
authors.lastname: Shen
authors.forename: Ruqin
authors.initials: R
authors.lastname: Yu
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D055664:Electrochemical Techniques / Q000379:methods*; D057075:Enzyme Assays / Q000379:methods; D006735:Horseradish Peroxidase / Q000378:metabolism; D008628:Mercury / Q000032:analysis*; D015345:Oligonucleotide Probes / Q000737:chemistry*; D012680:Sensitivity and Specificity
chemical_list: D001426:Bacterial Proteins; D015345:Oligonucleotide Probes; C058865:Strep-avidin conjugated horseradish peroxidase; D006735:Horseradish Peroxidase; D008628:Mercury