The interactions among protein nanocages and their stability against aggregation in suspension were discovered to be highly pH-dependent, with reversible aggregation into micron-sized aggregates occurring at lower pH, close to their isoelectric point. The stimuli-responsive aggregation and de-aggregation of phages could enable the targeted delivery of high concentrations of phages to specific areas in the body. Our group has recently discovered pHresponsive hexagonally structured supraparticles from self-assembly of the 27 nm diameter Escherichia coli (E.coli) bacteria virus Qubevirus durum (Qbeta) with the polycation poly [2-(methacryloyloxy)ethyl] trimethylammonium chloride (pMETAC) of defined chain length. This self-assembly is primarily driven by the specific adsorption of pMETAC onto the virus capsid surface, followed by anisotropic electrostatic interactions. Notably, the phage remains biologically active within the assembled structures. The supraparticles could be disassembled by external triggers, such as changes in the pH or the salt concentration in the suspension, to release the fully active phages.