Site-Specific In Situ Metallization of Wireframe DNA Origami for Reversible Fluorescence Switching

The addressability of DNA origami nanostructures enables the site-specific positioning of functional materials with nanometer-scale precision. DNA origami-templated gold nanoparticles have attracted broad interest due to their tunable optical and electronic properties. In this study, we develop a bottom-up nanofabrication strategy that integrates a rationally designed chemical handle that contains an iodobenzene derivative into a wireframe DNA origami template to direct the capture and in situ reduction of gold ions, achieving site-specific metallization. We then incorporate a fluorescent Cy3 dye into the metallized origami template to show the distance-dependent fluorescence quenching via energy transfer. As a proof of concept, we also demonstrate the dynamic programmability of the hybrid system to remove the fluorophore by using a strand displacement reaction, resulting in complete fluorescence recovery.