期刊
ELECTROANALYSIS
卷 22, 期 2, 页码 244-250出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/elan.200904698
关键词
Electrochemical immunosensor; Colloidal gold-based dentritical enzyme complex; Signal amplification; alpha-Fetoprotein; Enzymes; Nanoparticles
资金
- 973 National Key Basic Research Program [2007CB310500]
- National Nature Science Foundation of China [20775023, 20675028, 20875027, J0830415]
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.
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