Rapid Identification of the Receptor-Binding Specificity of Influenza A Viruses by Fluorogenic Glycofoldamers

The re-emergence of influenza raises a global concern that viral pandemics can unpredictably occur. However, effective approaches that can probe the infection risk of influenza viruses for humans are rare. In this work, we develop a glycofoldamer that can rapidly identify the glycan-receptor specificity of influenza viruses in a high-throughput manner. The coupling of glycan receptors that can be recognized by hemagglutinin (a surface protein on the virion capsid of influenza) to a fluorogenic-dye foldamer produces the glycofoldamers with minimal fluorescence in aqueous solution. After interaction with human-infecting virus strains for only five minutes, the fluorescence intensity of the glycofoldamer is remarkably enhanced with a blue-shifted emission peak. The probes have also proven effective for the rapid identification of 1) the human- or bird-infecting properties of influenza viruses in a high-throughput manner and 2) the receptor-specificity switch of a virus strain by mutations.