Immobilization of Acetylcholinesterase onto Carbon Nanotubes Utilizing Streptavidin-biotin Interaction for the Construction of Amperometric Biosensors for Pesticides

Abstract

Carbon nanotubes (CNTs) are very promising materials onto which bioactive molecules can be immobilized in the construction of biosensors. Streptavidin was used as a molecular linker to immobilize biotinylated acetylcholinesterase (AChE) on CNTs in a gentle and controllable fashion for pesticide biosensors. Glassy carbon electrodes coated with the CNT-enzyme complex had high affinity for the substrate acetylthiocholine and produced strong peak oxidation currents in electrochemical assays. We also propose a new method, i.e., the use of relative net slope rather than the percentage of inhibition, in the calculation of pesticide concentrations. The biosensors could detect low levels of the pesticide methyl paraoxon.

Keywords:

• Acetylcholinesterase
• biosensor
• carbon nanotubes
• methyl paraoxon
• pesticides
• streptavidin-biotin interaction

The work was funded by the Sensors and Sensor Network Theme, CSIRO. The authors would like to thank Dr. Stephen Hawkins for his role in supplying the CNTs used in this study.