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

摘要

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.