摘要

A sensitive and specific electrochemical immunosensor was developed with alpha-fetoprotein (AFP) as the model analyte by using gold nanoparticle label for enzymatic catalytic amplification. A self-assembled monolayer membrane of mercaptopropionic acid (MPA) was firstly formed on the electrode surface through gold-sulfur interaction. Monoclonal mouse anti-human AFP was covalently immobilized to serve as the Capture antibody. In the presence of the target human AFP. gold nanoparticles coated with polyclonal rabbit anti-human AFP were bound to the electrode via the formation of a sandwiched complex. With the introduction of goat anti-rabbit IgG conjugated with alkaline phosphatase, the dentritical enzyme complex was formed through selective interaction of the secondary antibodies with the colloidal gold-based primary antibody at the electrode. thus affording the possibility of signal amplification for AFP detection. Current response arising front the oxidation of enzymatic product was significantly amplified by the dentritical enzyme complex. The current signal vas proportional to the concentration of AFP from 1.0 ng mL(-1) to 500 ng mL(-1) with a detection limit of 0.8 ng mL(-1). This system could be extended to detect other target molecules with the corresponding antibody pairs.

  • 出版日期2010-1
  • 单位河南城建学院; 化学生物传感与计量学国家重点实验室; 湖南大学