A Novel Amperometric Immunosensor Based on Thionine/DNA Self-Assembled Multilayers on Carbon Nanotubes Modified Glass Carbon Electrode

A novel amperometric immunosensor for the determination of alpha-fetoprotein (AFP) was constructed using multi-wall carbon nanotubes modified glass carbon electrode.thionine as the mediator,were immobilized by DNA throngh the layer-by-layer method. Thionine was first fabricated on carbon nanotubes modified glass carbon throngh 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide(EDC/NHS).then a negatively charged DNA film was absorbed on the positively charged thionine,and the DNA was uesd as cross-linker to immobiled amount thionine.nano-Au-was used to immobilized anti-AFP.The electrochemical sensor have a relatively low detection limit of 0.02ng/ml.