Monomer Architecture as a Mechanism to Control the Self-Assembly of Oligomeric Diblock Peptide-Polymer Amphiphiles

Abstract

Diblock oligomeric peptide-polymer amphiphiles (PPAs) are biohybrid materials that offer versatile functionality by integrating the sequence-dependent properties of peptides with the synthetic versatility of polymers. Despite their potential as biocompatible materials, the rational design of PPAs for assembly into multi-chain nanoparticles remains challenging due to the complex intra- and intermolecular interactions emanating from the polymer and peptide segments. To systematically explore the impact of monomer architecture on nanoparticle assembly, PPAs were synthesized with a random coil peptide (XTEN2) and oligomeric alkyl acrylates with unique side chains: ethyl, tert-butyl, n-butyl, and cyclohexyl. Experimental characterization using electron and atomic force microscopies demonstrated that tail hydrophobicity impacted accessible morphologies. Moreover, characterization of different assembly protocols (i.e., bath sonication and thermal annealing) revealed that certain tail architectures provide access to kinetically trapped assemblies. All-atom molecular dynamics simulations of micelle structure formation unveiled key interactions and differences in hydration states, dictating PPA assembly behavior. These findings highlight the complexity of PPA assembly dynamics and serve as valuable benchmarks to guide the design of PPAs for a variety of applications including catalysis, mineralization, targeted sequestration, antimicrobial activity, and cargo transportation