Controlled nucleation and growth of surface-confined gold nanoparticles ona (3-aminopropyl)trimethoxysilane-modified class slide: A strategy for SPRsubstrates

The thickness of the gold film and its morphology, including the surface ro ughness, are very important for getting a good, reproducible response in th e SPR technique. Here, we report a novel alternative approach for preparing SPR-active substrates that is completely solution-based. Our strategy is b ased on self-assembly of the gold colloid monolayer on a (3-aminopropyl)tri methoxysilane-modified glass slide, followed by electroless gold plating. U sing this method, the thickness of films can be easily controlled at the na nometer scale by setting the plating time in the same conditions. Surface r oughness and morphology of gold films can be modified by both tuning the si ze of gold nanoparticles and agitation during the plating. Surface evolutio n of the Au film was followed in real time by UV-vis spectroscopy and in si tu SPRS. To assess the surface roughness and electrochemical stability of t he Au films, atomic force microscopy and cyclic voltammetry were used. In a ddition, the stability of the gold adhesion is demonstrated by three method s. The as-prepared Au films on substrates are reproducible and stable, whic h allows them to be used as electrodes for electrochemical experiments and as platforms for studying SAMs.