A strategy for making synthetic nano-particulate materials capable of recognizing viruses is reported in Nature Communications this week. The organic-inorganic composite materials demonstrate selective recognition of viral particles at ultra-low concentrations in water, and may lead to applications in virus production and diagnostics and ultimately, therapy. Materials capable of recognizing small molecules are widely reported but the recognition of viruses is harder due to their larger size. Patrick Shahgaldian and his colleagues use the viruses themselves as templates and then grow a layer of organosilica around the virus. The removal of the virus leaves an imprint which has the correct size and shape to selectively bind that virus. It is this process of creating a template that leads to the high performance and selectivity of the material.