Electrochemical Characterization of Streptavidin-HRP Immobilized on Multiwall Carbon Nanotubes for Biosensor Applications

摘要

In this work, we used gold labeled multiwall carbons nanotubes for peroxidase biosensor. The gold labeling on multiwall carbon nanotubes can be achieved with Pressure vapor Deposition (PVD) technique. The obtained carbon nanotubes can be immobilized on gold electrode with the airbrushing technique. The stability and the molecular structure of the labeled multiwall carbon nanotubes were characterized with cyclic voltammetry, impedance spectroscopy and Fourrier Transform Infra-Red spectroscopy (FTIR). It shows a higher conductivity and a good stability in water interface. For streptavidin-HRP immobilization, the labeled gold nanotubes were activated over night with thiol-acid (16 carbons). An activation procedure was achieved with EDC/NHS for HRP-streptavidin immobilization. The development of biosensor for H2O2 detection was observed with the impedance spectroscopy and cyclic voltammetry techniques. This method could be used to determine total H2O2 concentration in the range 4 μM - 160 μM. The results show that the biosensor response depends on the conductivity and the large surface-to-volume ratio attained with multiwall carbon nanotubes. The response of the developed biosensors was reproducible with higher stability.