Gold Nanoparticles in DNA‐Based Multilayer Films: Synthesis, Size Control, and Influence of the Multilayer Structure on Catalytic Properties

Abstract A method to prepare DNA‐based multilayered microcapsules as a host matrix for synthesizing ultrasmall gold nanoparticles of 2–4 nm in size is presented. Utilizing the intrinsic affinity of DNA for transition metal ions, ionic gold was first efficiently concentrated inside the DNA‐based multilayers assembled on a CaCO₃ sacrificial template. Further reduction of ionic gold inside the multilayers resulted in the formation of high‐density, well‐dispersed 2–4 nm gold nanoparticles distributed evenly and exclusively inside the polyelectrolyte multilayers. Metallized multilayers containing ultrafine gold nanoparticles showed a good performance in catalytic reduction of nitroaromatic compounds and the catalytic activity of gold nanoparticles was enhanced with a decrease of host multilayer thickness. The influence of the multilayer structure and composition on size and catalytic activity of gold nanoparticles is discussed.