Label-Free and Microplate-Based Dissection of Glycan-Virus Interactions Using Polymer-Tethered Glyconanoparticles

Influenza viruses use haemagglutinins (HA) to target host sialic acids in the respiratory tract as do other pathogens, including coronaviruses, which engage using spike protein. The host adaptation of the HA protein, which leads to the accumulation of mutations, is a key descriptor of individual influenza strains, which aids zoonosis and is crucial in vaccine development. How each strain targets glycans is crucial to understanding function, designing new therapies, and optimizing candidates for vaccine development. Here, it is demonstrated that polymer-tethered plasmonic (gold) glyconanoparticles can be deployed for rapid evaluation of whole influenza virus binding, readable by simple UV-vis within a microwell plate as a low-tech alternative to printed microarrays. It is also demonstrated that the synthetic methodology is compatible with large branched glycans from chemoenzymatic synthesis, allowing a wider range of glycan structures to be probed. Particles are obtained by a modular capture and immobilisation process and used to interrogate the binding of five influenza strains as proof of concept. These results show that glycosylated nanoparticle probes are suitable for the rapid interrogation of live virus to map how glycan structure impacts binding and can enable at-bench, rapid virus/glycan binding readouts and aid the development of interventions for influenza and other viruses.