title: [Cu(phen)2](2+) acts as electrochemical indicator and anchor to immobilize probe DNA in electrochemical DNA biosensor.
abstract: We demonstrate a novel protocol for sensitive in situ label-free electrochemical detection of DNA hybridization based on copper complex ([Cu(phen)2](2+), where phen = 1,10-phenanthroline) and graphene (GR) modified glassy carbon electrode. Here, [Cu(phen)2](2+) acted advantageously as both the electrochemical indicator and the anchor for probe DNA immobilization via intercalative interactions between the partial double helix structure of probe DNA and the vertical aromatic groups of phen. GR provided large density of docking site for probe DNA immobilization and increased the electrical conductivity ability of the electrode. The modification procedure was monitored by electrochemical impedance spectroscopy (EIS). Square-wave voltammetry (SWV) was used to explore the hybridization events. Under the optimal conditions, the designed electrochemical DNA biosensor could effectively distinguish different mismatch degrees of complementary DNA from one-base mismatch to noncomplementary, indicating that the biosensor had high selectivity. It also exhibited a reasonable linear relationship. The oxidation peak currents of [Cu(phen)2](2+) were linear with the logarithm of the concentrations of complementary target DNA ranging from 1 × 10(-12) to 1 × 10(-6) M with a detection limit of 1.99 × 10(-13) M (signal/noise = 3). Moreover, the stability of the electrochemical DNA biosensor was also studied.
authors.affiliation: Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
authors.forename: Linlin
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China. Electronic address: chemlixi@whut.edu.cn.
authors.forename: Xi
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
authors.forename: Songling
authors.initials: S
authors.lastname: Yan
authors.affiliation: Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
authors.forename: Yinna
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.affiliation: Department of Chemistry, School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China.
authors.forename: Yulin
authors.initials: Y
authors.lastname: Dong
authors.affiliation: School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, People's Republic of China. Electronic address: polymers@whut.edu.cn.
authors.forename: Chaocan
authors.initials: C
authors.lastname: Zhang
mesh_terms: D015374:Biosensing Techniques; D004247:DNA / Q000032:analysis* / Q000378:metabolism; D015342:DNA Probes / Q000737:chemistry / Q000378:metabolism*; D058266:Dielectric Spectroscopy; D055664:Electrochemical Techniques; D004566:Electrodes; D006108:Graphite / Q000737:chemistry; D057230:Limit of Detection; D009693:Nucleic Acid Hybridization; D010618:Phenanthrolines / Q000737:chemistry*
chemical_list: D015342:DNA Probes; D010618:Phenanthrolines; C014741:bis(1,10-phenanthroline)copper(2+) ion; D006108:Graphite; D004247:DNA
keywords: Copper complex; Electrochemical DNA biosensor; Graphene; Square-wave voltammetry