Preparation of one- to four-branch silver nanostructures of various sizes by metallization of hybrid DNA–protein assemblies

Abstract

We exploit the versatility of DNA–protein assemblies to generate branched metal nanostructures, referred to as nanoshurikens, of various sizes and degrees of branching. Branched silver nanostructures are prepared by metallization of star-shaped DNA–protein templates composed of monobiotinylated DNA molecules surrounding a single streptavidin protein core. DNA–protein templates are prepared by direct assembly that results in a mixture of 1-, 2-, 3- and 4-branch structures that can be separated by gel electrophoresis. A one-pot, bulk metallization is then performed in situ by successive addition of silver nitrate and sodium borohydride. This results in branched metal nanostructures with one to four branches of a well-defined length that is about 3-fold shorter than that of the template. We show that it is possible to tune two structural parameters: (i) the degree of branching by varying the concentration of streptavidin and (ii) the branch length (from 21 ± 5 nm to 107 ± 22 nm) by using biotinylated DNA molecules of different sizes.