Colloidal Crystallization of Virus‐Like Particles with Polycations

Abstract Virus‐like particles (VLPs) are protein nanocages capable of encapsulating or attaching guest molecules. Unlike viruses, they do not replicate in cells, making them promising candidates for advanced biomaterial design, particularly for biomedical applications such as drug delivery. However, the mechanisms governing VLPs self‐assembly into highly ordered suprastructures with enhanced functionality remain largely unexplored. This study investigates the development of pH‐responsive biomaterials using the icosahedral Acinetobacter phage coat protein AP205 VLPs, which has a diameter of ≈28 nm. Small‐angle X‐ray scattering, dynamic light scattering, and zeta‐potential measurements reveal that AP205 VLPs self‐assemble with the polycation poly[2‐(methacryloyloxy)ethyl] trimethylammonium chloride (pMETAC) into highly ordered suprastructures. The structural organization is strongly influenced by composition, pH, and ionic strength. The findings provide insights into the directional interactions governing VLPs self‐assembly with polycations and can guide the design of advanced, tunable VLP‐based biomaterials.