pH‐Responsive Virus‐Based Colloidal Crystals for Advanced Material Platforms

Abstract

Bacteriophages have a well‐defined nanoscale size, shape, and surface chemistry, making them promising candidates for creating advanced biomaterials for applications including biocatalysis, drug delivery, and biosensing. This study demonstrates the self‐assembly of the ≈29 nm diameter bacteriophage Qbeta (Qubevirus durum) with the synthetic polycation, poly [2‐(methacryloyloxy)ethyl] trimethylammonium chloride (pMETAC), into compartmentalized colloidal crystals. The pH and the polymer chain length tune their self‐assembly and the resulting structure, with the potential for further chemical modification or loading with bioactive molecules. Small angle X‐ray scattering (SAXS), multi‐angle dynamic light scattering (DLS), and atomic force microscopy (AFM) are used for studying the Qbeta self‐assembly into the geometrically ordered aggregates. The suprastructures form at pH > 7.0 and disassemble at pH < 7.0. Zeta potential measurements and X‐ray photoelectron spectroscopy (XPS) show pMETAC adsorption onto the negatively charged Qbeta surface. The colloidal crystal formation is achieved without chemically modifying the Qbeta surface. Additionally, the Qbeta/pMETAC suprastructures can be easily separated from the suspension as macroscopic aggregate, maintaining their activity. Their simple preparation allows for large‐scale production of advanced materials in food and health science applications and nanotechnology. The insights from this study will further advance the tailored design and production of novel colloidal materials.