Biomimetic Architectures for the Impedimetric Discrimination of Influenza Virus Phenotypes

Rapid discrimination of avian vs. human phenotypes of emerging influenza A virus isolates with pandemic potential is an important issue in pathogenesis and epidemiology studies of the infection. In this work, functional architectures are tailored on the surface of a gold electrode, introducing receptor molecules as a sensing entity that mimics those found in the membrane of target cells of the influenza A virus and with the aim of developing an impedimetric-based detector for influenza A virus phenotyping. In a bottom-up approach, the artificial receptors are built by sequential assembly of a 1-octanethiol/octyl-galactoside hybrid bilayer, followed by an enzyme-mediated functionalization of the terminal galactoside groups with sialic acid molecules. The detection mechanism relies hence on the specific affinity between the sialic acid-galactose receptor moieties anchored on the modified electrode surface and the hemagglutinin (HA) viral surface protein. By using the appropriate type of sialyltransferase enzyme, sialylation of galactose residues is made through a-2,3 or a-2,6 linkages. This permits the envisaged impedimetric detector to discriminate rapidly between avian vs. human strains of influenza A virus with the absence of elaborate sample preparation steps. In contrast to immunosensors based on antibodies as bioreceptor, the sialylated modified gold electrode is also able to distinguish among influenza phenotypes, which could make the here presented detector a reagentless, label-free diagnostic device for influenza phenotyping.