Self-Assembly of Hierarchically Structured Materials From Liquid Crystalline Mesophases of Tobacco Mosaic Virus-Like Particles.

Abstract

Many biological materials owe their impressive performance to the hierarchical organization of protein subunits across multiple length scales, motivating next generation bio-inspired material design. However, limited understanding of the mechanisms by which proteins self-assemble into higher-order structures hinders our ability to mimic nature. Here, we demonstrate that recombinantly produced Tobacco Mosaic Virus coat proteins (TMVcp) can self-assemble into hierarchically structured macroscopic materials using a lyotropic liquid crystal (LC) as a transient precursor phase. TMVcp helical rods were formed under controlled pH and ionic conditions, then processed into macroscale filamentous structures using a drying droplet technique, which effectively mimics fabrication of biological fibers combining mechanical shear and dehydration. Polarized light microscopy (PLM) of the fluid phase revealed birefringence, indicating liquid crystalline alignment, while polarized confocal Raman spectroscopy confirmed the retention of the native TMVcp folded structure within the assembled filaments. Synchrotron small-angle x-ray scattering (SAXS) further revealed tight hexagonal packing of TMVcp helical rods, which are aligned along the filament axis, indicating a highly ordered nanoscale organization. These results highlight the potential of virus-like particles (VLPs) as model systems for elucidating and engineering the self-assembly of hierarchical biomaterials, opening new avenues for the development of sustainable, tunable protein-based materials for advanced applications.