title: Nucleic acid-modulated silver nanoparticles: a new electrochemical platform for sensing chloride ion.
abstract: Inorganic nanomaterials have generated considerable interest in connection to the design of biosensors. Here we exploit the DNA-induced generation of silver nanoparticles for developing an electrical biosensing protocol for chloride ions. Conjugated with thiol modified oligonucleotide, silver nanoparticles were template-synthesized and immobilized on gold electrode. During cyclic voltammogram (CV) scans, the silver nanoparticles were oxidized at high potential to form a layer of Ag/AgCl complex in the presence of Cl(-), giving off sharp solid state redox signals. Under the optimum condition, the electrode responded to Cl(-) over a dynamic range of 2.0 × 10(-5)-0.01 M, with a detection limit of 5.0 × 10(-6) M. Moreover, the specific solubility product constant-based anion recognition made the electrode applicable at a wide pH range and in complex biological systems. To demonstrate the analytical applications of this sensor in real samples, the Cl(-) concentrations in human urine were measured without any sample pretreatment. Urinary Cl(-) detected by the proposed sensor ranged from 110 to 200 mM, which was comparable to the results obtained by standard silver titration.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
authors.forename: Jianyu
authors.initials: J
authors.lastname: Jin
authors.forename: Xiangyuan
authors.initials: X
authors.lastname: Ouyang
authors.forename: Jishan
authors.initials: J
authors.lastname: Li
authors.forename: Jianhui
authors.initials: J
authors.lastname: Jiang
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Wang
authors.forename: Ronghua
authors.initials: R
authors.lastname: Yang
mesh_terms: D015374:Biosensing Techniques; D002712:Chlorides / Q000652:urine*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006801:Humans; D007477:Ions / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009841:Oligonucleotides / Q000737:chemistry*; D010084:Oxidation-Reduction; D012834:Silver / Q000737:chemistry*
chemical_list: D002712:Chlorides; D007477:Ions; D009841:Oligonucleotides; D012834:Silver