An acetylcholinesterase enzyme electrode stabilized by an electrodeposited gold nanoparticle layer

Electrodeposition of colloidal gold nanoparticles onto a planar gold electrode was used to create a more favorable surface for the attachment of the enzyme acetylcholinesterase. Atomic force microscopy demonstrated that the gold nanoparticles roughened the surface consequently enhancing the interaction of the enzyme with the gold electrode. The enzyme-modified electrode sensor was utilized for the sensitive electrochemical detection of thiocholine at the gold surface after hydrolysis of acetylthiocholine by the immobilized enzyme. In the absence of the nanoparticle layer, the sensor response to acetylthiocholine was significantly reduced and the utility of the electrode was limited. The ability of the nanoparticle-based sensor to reliably measure concentrations of the organophosphate pesticide carbofuran at nM concentrations was demonstrated by monitoring the inhibition of the hydrolysis of acetylthiocholine. This relatively straightforward strategy is potentially valuable for the development of new devices for the sensitive detection of potentially dangerous and deadly neurotoxins.