Site-specific in situ synthesis of eumelanin nanoparticles by an enzymatic autodeposition-like process.

A method for in situ formation and controlled deposition of eumelanin nanoparticles is presented. The particles are built up by enzymatic reaction of l-DOPA with tyrosinase. The enzyme is tethered onto the support surface to get site-specific deposition of eumelanin. Due to the immediate deposition, the particles are monodisperse, with diameters of about 30-60 nm. Up to now, eumelanin particles have only been observed with sizes of about 200 nm. Deposition of those particles is site-specific on the areas where enzyme is present and results in different kinds of patterns on the support surface, including versatile monolayer structures.