Influence of various colloidal surfactants on the stability of MS2 bacteriophage suspension. The charge distribution on the PCV2 virus surface

To understand virus stability in aqueous solutions, the colloidal nanostructure and properties of a model virus, the MS2 bacteriophage, have been investigated by studying the effect of the addition of electrolytes and various colloidal surfactants to its water solution at physiological conditions. The charge of the virus particles influences their colloidal properties. It was found that the ζ-potential value is reduced from –35 mV to –10 mV in 0.01 M CaCl₂ and 0.1 M NaCl solutions as well as at higher electrolytes concentrations, while the size of the MS2 aggregates was about 600 ÷ 900 nm with individual particles of size around 30 nm also recorded. The 2: 1 electrolyte causes destabilization of MS2 bacteriophage particles in an aqueous solution at a lower concentration. The addition of cationic, anionic, and non-ionic colloidal surfactants below and above critical micelle concentration to MS2 bacteriophage suspension caused the destabilization of MS2 particles. We also investigated the capsid's surface of another virus, PCV2, using dynamic light scattering and laser Doppler electrophoresis. The hydrodynamic diameter and the ζ-potential of PCV2 empty capsid were found to be equal to 22 ± 1 nm and −41 ± 4 mV (using Ohshima approximations). The electrostatic potential of the surface was measured using acid-base probes and found to be equal to −91 ± 3 and +14 ± 2 mV for positively and negatively charged probes respectively, which indicate the ‘mosaic’ way of the charge distribution on the surface, similar to MS2′s surface studied previously. Our data provide new information about the virus surface, the complex process of virus aggregation-disaggregation and virus capsid disassembly.