Lattice self-assembly of cyclodextrin complexes and beyond

While lipids form soft, fluidic membranes (soft assembly), proteins can readily assemble into rigid, crystalline structures such as viral capsids and bacterial compartments (lattice assembly). The key difference has to do with the driving forces, where the former is driven by the weak, directionless hydrophobic effect and the latter, by a combination of relatively strong, directional intermolecular interactions. In synthetic systems, the lipid assembly has been massively replicated but the protein assembly has been rarely rivaled. Herein, we briefly review these two kinds of assemblies with special emphasis on a recently reported lattice self-assembly system of cyclodextrin complexes. The complexes arrange themselves into an in-plane, rhombic lattice that develops into lamellar, tubular, and polygonal structures depending on concentration. We will then cover the formation mechanisms, driving forces, and an application of the tubes in particle encapsulation. We hope that this short review would draw people's attention to this emerging field of lattice self-assembly.