Macromolecular Cargo Encapsulation via In Vitro Assembly of Two-Component Protein Nanoparticles.

Self-assembling protein nanoparticles are a promising class of materials for targeted drug delivery. Here we report the use of a computationally designed, two-component icosahedral protein nanoparticle to encapsulate multiple macromolecular cargoes via simple and controlled self-assembly in vitro. Single-stranded RNA molecules between 200 and 2500 nucleotides in length were encapsulated and protected from enzymatic degradation for up to a month with length-dependent decay rates. Immunogenicity studies of nanoparticles packaging synthetic polymers carrying a small-molecule TLR7/8 agonist showed that co-delivery of antigen and adjuvant resulted in a more than 20-fold increase in humoral immune responses while minimizing systemic cytokine secretion associated with free adjuvant. Coupled with the precise control over nanoparticle structure offered by computational design, robust and versatile encapsulation via in vitro assembly opens the door to a new generation of cargo-loaded protein nanoparticles that can combine the therapeutic effects of multiple drug classes. This article is protected by copyright. All rights reserved.