Research by Carlos Duque, Doug Hall*, Botond Tyukody and Greg Grason* was recently published in PNAS and demonstrates economical assembly of size-tailored, triply-periodic minimal surfaces via "inverted" Caspar-Klug design principles. This work is entitled, Limits of economy and fidelity for programmable assembly of size-controlled triply periodic polyhedra.
As first suggested by Caspar and Klug, many viruses assemble icosahedral shells (capsids) because the high symmetry of the icosahedron enables economical assembly—enclosing a large volume with relatively few distinct protein subunit types. We generalize this design principle to triply periodic polyhedra, mesoporous structures approximating cubic minimal surfaces. We demonstrate their programmable assembly from a minimal number of distinct subunits forming arbitrarily large unit cells of tunable, defined size. However, while high symmetry points enable economy in these target structures, they can be seeds of misassembly. This design strategy, and the fundamental tradeoff between economy and fidelity, lays the groundwork for deploying rapidly advancing nanotechnology approaches to programmable assembly to achieve size-controlled architectures with tunable functional properties.