A new strategy for label-free electrochemical immunoassay based on "gate-effect" of beta-cyclodextrin modified electrode

作者：Deng, Huan; Li, Jianping^*; Zhang, Yun; Pan, Hongcheng; Xu, Guobao^*

来源：Analytica Chimica Acta, 2016, 926: 48-54.

DOI：10.1016/j.aca.2016.04.035

• Electrochemical immunosensor
• Gate-effect
• beta-Cyclodextrin
• Prostate-specific antigen
• Probe current

A novel label-free electrochemical immunoassay was developed for prostate-specific antigen (PSA) detection via using beta-cyclodextrin (beta-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-beta-cyclodextrin. Interspaces among beta-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.

• 出版日期2016-7-5
• 单位电分析化学国家重点实验室; 中国科学院; 桂林理工大学; 中国科学院长春应用化学研究所