Yes / We report on the use of non-equillibrium biocatalytic self-assembly and gelation to guide the reductive synthesis of gold nanoparticles. We show that biocatalytic rates simultaneously dictate supramolecular order and presentation of reductive phenols which in turn results in size control of nanoparticles that are formed. / BBSRC funding (BB/K007513/1); European Research Council under the European Union’s Seventh Framework Programme, ERC (Starting Grant EMERgE) grant agreement no. 258775.