An ultrasensitive signal-on electrochemiluminescence biosensor based on Au nanoclusters for detecting acetylthiocholine

For improving the sensitivity of the electrochemiluminescent (ECL) detection and extending the applications of luminophore, the development of coreactant accelerator is one of the important ways. In this work, Au nanoclusters (Au NCs) were chosen as the luminescent material, and thiocholine, which was in situ generated by enzymatic reaction, was found to serve as a coreactant accelerator for Au NC-S2O82− ECL system. Based on this discovery, a highly sensitive detection of acetylthiocholine (ATCl) was achieved using the acetylcholinesterase (AChE) biosensor. CeO2 nanowires (CeO2 NWs) were used to improve the stability of Au NCs on the glassy carbon electrode (GCE) due to the large specific surface area and good film-forming properties of CeO2 NWs. ATCl was catalyzed by acetylcholinesterase (AChE) to produce thiocholine, which served as the coreactant accelerator to improve the ECL signal of Au NC-S2O82− system. The biosensor obtained a low detection limit of 0.17 nM. The integration of thiocholine and Au NCs would provide a new ECL platform for bioanalysis.