High-sensitivity pesticide detection via silicon nanowires-supported acetylcholinesterase-based electrochemical sensors

We report the use of a silicon-based nanocomplex, i.e., gold nanoparticles-coated silicon nanowires, for the improvement of acetylcholinesterase (AChE)-based electrochemical sensors for pesticide detection. Owing to the high electrical conductivity of the nanocomplex and its compatibility with the enzyme, the sensor exhibited significantly enhanced performance. The AChE enzyme bound to the surface possessed Michaelis-Menton constant of 81 mu M, resembling that in its free form. The sensor showed rapid response toward substrate acetylcholine in the concentration range of 1.0 mu M-1.0 mM. This AChE nanosensor could detect as low as 8 ng/L dichlorvos, an organophosphate pesticide. (C) 2008 American Institute of Physics.