title: Highly sensitive and selective electrochemical detection of Hg(2+) through surface-initiated enzymatic polymerization.
abstract: A Hg(2+) electrochemical biosensor is developed by integrating thymine-Hg(2+)-thymine (T-Hg(2+)-T) base pairs for the high selectivity with surface-initiated enzymatic polymerization (SIEP) for signal amplification. The fabrication begins with the covalent conjugation of capture DNA probe labeled with thiol at its 3'terminal onto the gold electrode. The presence of Hg(2+) leads to DNA hybridization, in which complementary DNA was captured onto the biosensor surface, which subsequently catalyzed the addition of deoxynucleotides (dNTP) containing biotinlated 2'-deoxyadenosine 5'-triphosphate (biotin-dATP) by terminal deoxynucleotidyl transferase (TdT). The binding between biotin and strepavidin leads to the attachment of a large number of strepavidin functionalized silver nanoparticles (strepavidin-AgNPs), which could generate electrochemical stripping signal of silver to monitor the concentration of Hg(2+) in KCl solution. Through utilizing the T-Hg(2+)-T selectivity and SIEP amplification, this assay method can detect aqueous Hg(2+) with a wide linear range from 0.05 nM to 100 nM and a detection limit of 0.024 nM. The application of this sensor in the analysis of drinking water demonstrates that the proposed method works well for real samples.
authors.affiliation: College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325037, PR China.
authors.forename: Chenyang
authors.initials: C
authors.lastname: Mei
authors.affiliation: School of Science and Engineering, Wenzhou University Oujiang College, Wenzhou 325037, PR China; State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210093, PR China. Electronic address: lindj@wzu.edu.cn.
authors.forename: Dajie
authors.initials: D
authors.lastname: Lin
authors.affiliation: School of Science and Engineering, Wenzhou University Oujiang College, Wenzhou 325037, PR China.
authors.forename: Chengchao
authors.initials: C
authors.lastname: Fan
authors.affiliation: College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325037, PR China.
authors.forename: Aili
authors.initials: A
authors.lastname: Liu
authors.affiliation: College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325037, PR China. Electronic address: shunwang@wzu.edu.cn.
authors.forename: Shun
authors.initials: S
authors.lastname: Wang
authors.affiliation: College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325037, PR China; Department of Chemistry and Biochemistry, University of Windsor, Canada, ON N9B 3P4, United States.
authors.forename: Jichang
authors.initials: J
authors.lastname: Wang
mesh_terms: D015374:Biosensing Techniques; D060766:Drinking Water / Q000737:chemistry*; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D008628:Mercury / Q000737:chemistry / Q000302:isolation & purification*; D053768:Metal Nanoparticles / Q000737:chemistry; D019809:Streptavidin / Q000737:chemistry
chemical_list: D060766:Drinking Water; D006046:Gold; D019809:Streptavidin; D008628:Mercury
keywords: Electrochemical sensor; Mercury; Signal amplification; Surface-initiated enzymatic polymerization; Thymine–Hg(2+)–thymine