title: A new strategy for label-free electrochemical immunoassay based on "gate-effect" of β-cyclodextrin modified electrode.
abstract: A novel label-free electrochemical immunoassay was developed for prostate-specific antigen (PSA) detection via using β-cyclodextrin (β-CD) assembled layer created gates for the electron transfer of probe. To construct the sensor, a gold electrode was self-assembled with monoclonal anti-PSA antibody labeled 6-mercapto-β-cyclodextrin. Interspaces among β-CD molecules in the layer were automatically formed on gold electrode, which act as the channel of the electron transfer of [Fe(CN)6](3-/4-) probe. When PSA bind with anti-PSA, it can block these channels on the electrode surface due to their steric hindrance effect, resulting in the decrease in redox current of the probe. Through such a gate-controlled effect, ultra trace amount of PSA may make the currents change greatly after the immunoreaction, which enhanced the signal-to-noise ratio to achieve the amplification effect. By evaluating the logarithm of PSA concentrations, the immunosensor had a good linear response to the current changes with a detection limit of 0.3 pg/mL (S/N = 3) when PSA concentration ranged from 1.0 pg/mL to 1.0 ng/mL. The label-free immunosensor exhibited satisfactory performances in sensitivity, repeatability as well as specificity.
authors.affiliation: College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, PR China.
authors.forename: Huan
authors.initials: H
authors.lastname: Deng
authors.affiliation: College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, PR China. Electronic address: likianping@263.net.
authors.forename: Jianping
authors.initials: J
authors.lastname: Li
authors.affiliation: College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, PR China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, PR China.
authors.forename: Hongcheng
authors.initials: H
authors.lastname: Pan
authors.affiliation: College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, PR China; State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. Electronic address: guobaoxu@ciac.ac.cn.
authors.forename: Guobao
authors.initials: G
authors.lastname: Xu
mesh_terms: D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D007118:Immunoassay / Q000379:methods*; D057230:Limit of Detection; D008855:Microscopy, Electron, Scanning; D017430:Prostate-Specific Antigen / Q000032:analysis; D015203:Reproducibility of Results; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D047392:beta-Cyclodextrins; D017430:Prostate-Specific Antigen; C031215:betadex
keywords: Electrochemical immunosensor; Gate-effect; Probe current; Prostate-specific antigen; β-Cyclodextrin