Two-Dimensional, Chiral Colloidal Superlattices Engineered with DNA Origami

Colloidal crystal engineering is widely recognized as a superior method for creating novel materials in multiple fields. However, achieving chiral superlattices of nanoparticles remains a considerable challenge so far. Here, we spread a two-dimensional (2D), microscale DNA origami array on substrate surfaces to maintain its planar conformation onto which DNA-encoded metal nanoparticles are attached to designated positions, thereby creating 2D chiral superlattices. By designing programmable chiral patterns of DNA sticky ends within the DNA origami units, we realize a variety of 2D chiral superlattices over large areas with well-defined chiral configurations of nanoparticle arrangements. The underlying chiral optical mechanism of the superlattices is revealed, showing the essential role of local plasmonic couplings within the repeating units. This research represents the first example of DNA-programmed 2D chiral superlattices of nanoparticles assembled directly on a substrate surface, with the potential to impact future studies in on-chip integrated metamaterials, photonics, optoelectronics, and related fields.