title: An electrochemical DNA sensor based on a layers-film construction modified electrode.
abstract: This work developed a relatively inexpensive and layers-film construction electrochemical sensor for DNA recognition and its performance was investigated. The Fe(3)O(4) magnetic nanoparticles-cysteine were immobilized on the carbon paste electrode (CPE) surface using magnetic force. Multiwalled carbon nanotubes (MWCNTs), gold nanoparticles (GNPs), and chitosan (Chi) were used successively to coat on the electrode surface. The thiolated capture probe was assembled and competitively hybridized with the target nucleic acid and biotinylated response probe. The electrochemical behavior was analyzed by cyclic voltammetry and electrochemical impedance spectroscopy. In addition, the sensor performance was also analyzed by introducing the notion of detection efficiency. The experimental results showed that although the electron transfer capability of the CPE is less strong than that of a metal electrode used in the DNA sensor, the materials modified on the CPE could significantly improve the performance. A detection limit of 1 nM of target DNA and a sensitivity of 2.707 × 10(3) mA M(-1) cm(-2) were obtained. Although the resulting detection limit was not remarkable, further experiments could improve it.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China. ezhangyi123@yahoo.com.cn
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Zeng
authors.forename: Lin
authors.initials: L
authors.lastname: Tang
authors.forename: Yuan-Ping
authors.initials: YP
authors.lastname: Li
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Chen
authors.forename: Ya
authors.initials: Y
authors.lastname: Pang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Chong-Ling
authors.initials: CL
authors.lastname: Feng
authors.forename: Guo-He
authors.initials: GH
authors.lastname: Huang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D048271:Chitosan / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry; D004247:DNA / Q000032:analysis*; D058266:Dielectric Spectroscopy; D055664:Electrochemical Techniques; D004566:Electrodes; D052203:Ferrosoferric Oxide / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry; D009693:Nucleic Acid Hybridization
chemical_list: D037742:Nanotubes, Carbon; D006046:Gold; D004247:DNA; D048271:Chitosan; D003545:Cysteine; D052203:Ferrosoferric Oxide