Electrochemical detection of AChE-induced gold nanostructure growth on disposable chips

Acetylcholinesterase (AChE)-induced growth of colloidal gold (AuNP) via the reduction of chloroauric acid (HAuCl4) using thiocholine (TCh) was investigated using differential pulse voltammetry (DPV). The growth of Au nanostructures on the surface of gold disposable electrochemical printed (DEP) chips was detected using the electrochemical reduction signal. A shift in the peak potential of Au reduction signal and an increase in the peak current intensity were observed in the presence of HAuCl4. The growth of gold nanostructures was also examined using a well-established colorimetric assay using Au nanoparticles (AuNPs). Assay results showed a larger blue shift in the presence of the AChE-acetylthiocholine (ATCh) complex, HAuCl4, and AuNP seeds in the solution indicating the reductive enlargement of the AuNPs. Based on these measurements, it was found that the increased Au nanostructure formation allowed for low reduction potentials as well as high intensity current signals to be produced. The AChE-induced formation of Au nanostructures on the DEP chip surface is a promising platform for the development of novel biosensors.