Programming the Valence and Orientation of Anisotropic Nanoparticles via Three-Dimensional DNA Ligand Encoding.

The geometric nature of anisotropic nanoparticles (NPs) gives rise to directional variations in their physicochemical properties, making the characteristics of their assemblies highly tunable by manipulating their three-dimensional (3D) spatial configurations. Surface modification with DNA ligands, which creates molecular recognition between NPs, offers a practical approach for self-assembling NPs into customized nanostructures with emergent collective properties. However, the regioselective modification of DNA ligands on the complex 3D surface of anisotropic NPs to create specific and directional bonds remains challenging. Here, taking gold nanorods (AuNRs) as representative anisotropic NPs, we develop a DNA ligand encoding strategy that chemically transfers the two-dimensional (2D) DNA patterns from DNA origami templates onto the 3D curved surface of AuNRs, programming their valence and orientation for self-assembly. A semiflexible DNA origami template is designed to wrap around the AuNR to ensure that customized DNA ligands are addressed to predetermined positions. These DNA ligands facilitate specific linkages between AuNRs and gold nanospheres (AuNSs), enabling the construction of various stereocontrolled AuNR-AuNS nanostructures. By regulating the arrangement shape of DNA ligands and combining sequence-orthogonal DNA ligands, we further demonstrate precise control over the orientation of individual AuNRs, allowing the assembly of AuNR structures with tunable optical chirality. This approach provides a versatile strategy for assembling anisotropic NPs into desired 3D structures in a scaffold-free manner, which advances the construction of promising nanodevices for photonic, information, and biomedical applications.