Engineering Elastin-Like Peptide-Based Nanoparticles displaying Variable Domain of the Heavy Chain of Heavy-Chain-Only Antibodies for SARS-CoV-2 Neutralization

Elastin-like polypeptides (ELPs) are self-assembling recombinant biopolymers that can be precisely engineered to display functional targeting ligands. In this study, we developed ELP-based nanoparticles (NPs) displaying the variable domain of the heavy chain of heavy-chain-only antibodies (VHHs) targeting the SARS-CoV-2 spike protein. By tuning VHH selection, multivalency, and surface display density, we created targeted ELP NPs capable of blocking entry of spike-protein-presenting virus-like particles (VLPs) and live viruses, with subnanomolar IC₅₀ values, significantly outperforming the monovalent VHH equivalents. Notably, optimizing multivalency and VHH density unlocked broad virus-neutralizing potency against multiple variants, including Omicron variants resistant against the monovalent VHH equivalents. Confocal imaging further revealed that VHH-ELP NPs formed aggregates with VLPs, enhancing uptake by M1 macrophages, suggesting potential for eliciting vaccinal effects. Overall, this work highlights the versatility of ELP NPs as a tunable antiviral platform and provides design principles for next-generation nanotherapeutics against evolving viral threats.