para-Sulfonatocalix[4]arene stabilized gold nanoparticles multilayers interfaced to electrodes through host-guest...

Nanoparticle (NP) structure, compositing and the nature of the NP-functionalized electrode interface have a strong influence upon electrochemical properties that are critical in applications such as sensing, photocatalysis and electrocatalysis. Existing methods to fabricate NP-functionalized electrodes do not allow or precise control over all these variables, especially the NP-electrode interface, making it difficult to understand and predict how structural changes influence electrode activity and consequently limit the application. To conquer this problem, in this study, we fabricated a stepwise construction of a novel supramolecular stabilized gold nanoparticles (AuNPs) multilayer mediated by guest molecules, yielding 3D AuNPs assembly at the electrode interface. para-Sulfonatocalix[4]arene (pSC₄), a water soluble macrocyclic synthetic receptor, has been served as a stabilizing ligand for preparation and gaining new insights into pSC₄ stabilized gold nanoparticles (pSC₄-AuNPs) tethered on the electrode interface through host-guest interaction. We investigated the electrochemical properties of multilayer pSC₄-AuNPs modified gold electrode using different core size of AuNPs with varying layer number. The electron transfer ability was characterized by electrochemical impedance spectroscopy (EIS). Electrochemical signals are significantly enhanced through the layer-by-layer assembly of pSC₄-AuNPs due to its high conductivity and high effective area. With this innovative method, by taking the assay of a tumor marker as an example, human epidermal growth factor receptor 2 (ErbB2) was successfully measured with a detection limit of 0.5ng/mL. Taking the advantage of the pSC₄-AuNPs multilayer's good biocompatibility, high effective area and high electronic transmission, 3D AuNPs multilayer produced on the electrode interface suggests a portable synthetic pathway for the application into sensitive electrochemical biosensor.