Self-assembly of triply-periodic minimal surfaces from DNA-origami colloids

Self-assembly is a powerful bottom-up technique to fabricate intricate nanoscale structures with engineering applications. The geometry and topology of the target assemblies critically influence how they assemble. In this talk, I will present the results of an experimental study of the assembly of the Schwarz P-surface, a three-dimensional crystalline membrane with self-limited pores. Using triangular DNA-origami colloidal particles with specific edge-to-edge interactions and user-specified local curvature, we assemble a discretized, triangulated version of the Schwarz P-surface. We observe that thermal fluctuations in the local curvature generate polymorphic pore sizes that prevent long-range crystalline order. To mitigate this source of local polymorphism, we introduce additional subunit species to suppress the formation of low-lying off-target pore sizes. These samples with increased complexity are then able to crystallize. By tuning temperature to vary the binding strength, we find that strong binding yields gel-like aggregates and intermediate binding forms micrometer-scale nondefective crystallites. These findings highlight the importance of assembly complexity as a critical control parameter for limiting polymorphism in geometrically-programmed self-assembly. Further, we want to apply them to control the self-limited pore size of the crystal and assemble larger lattices with a higher triangulation number.