Abstract: In one aspect, a sensor for detecting SARS-CoV-2 virus in a sample, e.g., a blood sample, is disclosed, which includes a graphene layer, a plurality of binding agents coupled to said graphene layer to generate a functionalized graphene layer, where the binding agents exhibit specific binding to at least one epitope of SARS-CoV-2 virus, and a plurality of electrical conductors electrically coupled to said functionalized graphene layer for measuring an electrical property (e.g., DC electrical resistance) of the functionalized graphene layer. While in some embodiments such binding agents are monoclonal antibodies, in other embodiments they can be polyclonal antibodies.