Gold nanoparticles immobilization: Evidence of amination of diamond surfaces in liquid ammonia

Diamond presents many interesting properties in terms of biocompatibility, chemical inertness and is attractive for applications notably in the biosensor field. The formation of amine functional groups at diamond surface is of great interest for the incorporation of biomolecules. In the present work, we present an efficient direct amination method using anodic treatment in liquid ammonia on oxygen terminated diamond surface. Chemical surface modifications were followed by XPS analyses, while the distribution of amino-groups was indirectly studied by gold nanoparticles immobilization. The resulting surfaces were examined using FEG-SEM imaging. This combined approach has been powerful evidencing both the presence of notable amounts of amino groups after the electrochemical treatment in NH3liq and their homogeneous distribution at the diamond surface.

► Well dispersed C–NH2 functions can be efficiently produced on boron-doped diamond films by anodic treatment in liquid ammonia.
► The role of oxygen in the amination's of diamond efficiency is confirmed.
► Gold NPs immobilization is a good probe of the presence and distribution of amino groups.