DNA Origami Colloidal Crystals: Opportunities and Challenges.

Over the last three decades, colloidal crystallization has provided an easy-to-craft platform for mesoscale engineering of photonic and phononic crystals. Nevertheless, the crystal lattices achieved thus far with commodity colloids are largely limited to symmetric and densely packed structures, restricting their functionalities. To obtain non-close-packed crystals and the resulting complexity of the available structures, directional binding between "patchy" colloids has been pursued. However, the conventional "patchy" colloids have been restricted to micrometer-scale spherical particles or clusters. In this Mini-Review, we argue that the time has come to widen the scope of the colloidal palette and include particles made using DNA origami. By benefiting from its unprecedented ability to control nanoscale shapes and patch placement and incorporate various nanomaterials, DNA origami enables novel engineering of colloidal crystallization, particularly for photonic and phononic applications. This mini-review summarizes the recent progress on using DNA origami for colloidal crystallization, together with its challenges and opportunities.