Electrostatics-Driven Self-Assembly of Virus-like Particles into Arrays Mediated by Dendrimers*

Hierarchical self-assembly common in natural materials provides inspiration for designing synthetic materials with tailored structure and functionalities. Recent experiments have generated bulk materials including FCC superlattices using the P22 Virus-like Particle (VLP), a 60-nm protein cage, as a building block. This assembly into superlattices was mediated by oppositely charged, smaller dendrimers and controlled by tuning the ionic strength. In this study, coarse-grained molecular dynamics simulations are employed to explore charge and size complementarity of P22 VLPs and dendrimers in driving the hierarchical assembly in vitro. Equilibrium structures ranging from isolated VLPs to arrays of VLPs as a function of the ionic strength, VLP charge, and dendrimer permeability are identified and correlated with experiments. Structural properties including cluster size and pair correlation functions are evaluated. Results reveal the electrostatics-driven mechanism for dendrimer condensation on VLP surface and subsequent ordered agglomeration of VLPs. New avenues for exploiting long-range interactions in designing hierarchical, self-assembled materials are proposed.