We first develop a protocol for growing platinum films on SiO 2 microparticles without asymmetry, i.e. under bulk mixing conditions. Our method relies on the rapid complexation of cop- per ions by amine groups added to the SiO 2 microparticle surface , which reduces the time required for synthesis. By first complexing the ions onto the microparticle supports before performing the reduction step, the uncontrolled formation of metal nanoparticles upon addition of a strong reductant is virtually eliminated. An aqueous CuSO 2 solution is added drop-wise to an APTES-modified SiO 2 microparticle suspension under magnetic stirring. The solution is then washed by centrifugation to remove free ions from solution. The particles retain a light blue colour from the complexed copper ions. An aqueous NaBH 4 solution is then added dropwise to this mixture, which is left to react under magnetic stirring in an N 2 environment. The solution rapidly turns a dark-brown colour upon addition of the NaBH 4 , indicating the formation of Cu 0 nanoparticles, which are also visualised by SEM (Figure ). The resulting Cu-SiO 2 particles are then washed in degassed double-distilled water, retaining a brown colour from the Cu 0 nanoparticles attached onto their surface.