Elasticity as a control for self-assembling nanoscale building blocks

Designing reconfigurable materials based on deformable nanoscale building blocks hinges on an understanding of the role of elasticity in altering the self-assembly pathways. Most computational studies of self-assembly focus on coarse-grained models which employ rigid building blocks that do not exhibit shape adaptation during self-assembly. We study the self-assembly of elastic building blocks using the T=1 icosahedral virus system as an example. Coarse-grained models of viral capsomers that incorporate their bending and stretching energies are developed and simulated using molecular dynamics. Simulations reveal transitions from non-assembled configurations to icosahedral capsids to malformed structures with bending modulus as a control parameter. Increasing elasticity reverses incorrect capsomer-capsomer binding, facilitating transitions from malformed structures to symmetric capsids, however, making capsomers too soft inhibits assembly and yields fluid-like structures. Insights into the pronounced effects of changing block elasticity are obtained by linking the error correction during self-assembly to the enhanced fluctuations and entropic freedom associated with the softer building blocks.<br type="_moz" />