Multilayered ordered arrays self-assembled from a mixed population of nanoparticles

An experimentally-informed coarse-grained model is presented to probe the self-assembly of multiple types of charged nanoparticles in a one-pot mixture in the presence of oppositely charged linkers across a broad range of nanoparticle charge and ionic strength of the solution. The model is applied to study the self-assembly of negatively-charged bacteriophage P22 virus-like particles (VLPs) of different types, with each type comprising VLPs of a distinct surface charge, in the presence of positively-charged polyamidoamine (PAMAM) generation-6 (G6) dendrimers. The model accurately captures the self-assembly of one-component systems, including the assembly states of the highest-charged P22 variant that were inaccessible with earlier models, revealing that P22 VLPs assemble into ordered arrays below a threshold ionic strength that increases with increasing variant charge, consistent with experiments. Molecular dynamics simulations of two, three, and four-component mixtures of P22 VLPs show that changing the ionic strength gradually over the range of well separated threshold ionic strengths via dialysis generates hierarchical assembly of ordered multilayered core-shell structures, with each layer comprising VLPs of a single variant type. A quick decrease in the ionic strength via rapid dilution leads to amorphous aggregates with a mixed composition of different variants. The mechanisms driving the VLPs into different macrostructures are explored by examining the bound and bridging dendrimers associated with the different types of VLPs. Simulation findings are consistent with experiments and establish salt dialysis as a simple and versatile strategy to engineer multilayered and ordered structures via a single-pot synthesis of multiple types of nanoscale building blocks.