  The electrostatic interaction of metal nanoparticles with viruses is
attracting great interest due to their antiviral activity and their role in
enhancing the detection of viruses at ultra-low concentrations. We model the
MS2 virus devoid of its single strand RNA core using a core-shell model. The
dependence of the inner and outer surface charge density on the pH is taken
into account in our model of the interaction. Varying the pH causes a change in
the sign of the outer surface charge leading to the attractive-repulsive
transition in the electrostatic interaction between the MS2 virus and metal
nanoparticle at pH = 4.
