title: Sensitive impedimetric biosensor based on duplex-like DNA scaffolds and ordered mesoporous carbon nitride for silver(I) ion detection.
abstract: This study demonstrates a new, unlabeled immobilized DNA-based biosensor with ordered mesoporous carbon nitride material (MCN) for the detection of Ag(+) by electrochemical impedance spectroscopy (EIS) with [Fe(CN)6](4-/3-) as the redox couple. The unlabeled immobilized DNA initially formed the hairpin-like structure through hybridization with the probe, and then changed to duplex-like structure upon interaction with Ag(+) in solution to form a C-Ag(+)-C complex at electrode surface. As a result, the interfacial charge-transfer resistance of the electrode towards the [Fe(CN)6](4-/3-) redox couple was changed. Thus, a declined charge transfer resistance (Rct) was obtained, corresponding to Ag(+) concentration. MCN provide an excellent platform for DNA immobilization and faster electron transfer. Impedance data were analyzed with the help of Randles equivalent circuit. The lower detection limit of the biosensor for Ag(+) is 5 × 10(-11) M with good specificity. All results showed that this novel approach provides a reliable method for Ag(+) detection with sensitivity and specificity, potentially useful for practical applications. Moreover, other DNA detection methods for more heavy metals may be obtained from this idea and applied in the environmental field.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Ministry of Education, Changsha 410082, China. tanglin@hnu.edu.cn.
authors.forename: Yaoyu
authors.initials: Y
authors.lastname: Zhou
authors.forename: Lin
authors.initials: L
authors.lastname: Tang
authors.forename: Xia
authors.initials: X
authors.lastname: Xie
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
authors.forename: Jiajia
authors.initials: J
authors.lastname: Wang
authors.forename: Yaocheng
authors.initials: Y
authors.lastname: Deng
authors.forename: Guide
authors.initials: G
authors.lastname: Yang
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002414:Cations, Monovalent / Q000032:analysis; D015342:DNA Probes / Q000737:chemistry*; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D017097:Electric Impedance; D004867:Equipment Design; D061925:Immobilized Nucleic Acids / Q000737:chemistry*; D057230:Limit of Detection; D009570:Nitriles / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D016062:Porosity; D012722:Sewage / Q000032:analysis; D012834:Silver / Q000032:analysis*
chemical_list: D002414:Cations, Monovalent; D015342:DNA Probes; D061925:Immobilized Nucleic Acids; D009570:Nitriles; D012722:Sewage; D012834:Silver; C011206:cyanogen