Viral MRI contrast agents: coordination of Gd by native virions and attachment of Gd complexes by azide-alkyne cycloaddition

Icosahedral virus particles decorated with a Gd(DOTA) analogue by Cu-mediated azide-alkyne cycloaddition (CuAAC) and/or with Gd3+ ions by coordination to the viral nucleoprotein show increased T-1 relaxivity relative to free Gd(DOTA) complexes in solution.