The assembly of polydopamine (PDA) thin films by the spontaneous oxidative polymerization of a dopamine solution onto silica (SiO2) particles to form robust capsules, was demonstrated. A PDA film was deposited onto SiO 2 particles by the oxidative self-polymerization of dopamine. Nonporous SiO2 particles were exposed to a 2 mg mL dopamine solution in air at pH 8.5 in 10 mM tris(hydroxymethyl)aminomethane (TRIS) buffer for the allotted time and under constant agitation. The PDA-coated SiO2 particles were then washed several times in 10 mM TRIS buffer until the supernatant remained colorless. During the colloidal surface polymerization step, some particulate PDA was observed to form in solution. This was selectively removed by centrifugation during the washing steps. The single-step PDA deposition procedure produces polymer capsules with a wall thickness comparable to those formed by the conventional LbL (multistep) technique.