Polymer-Stabilized Sialylated Nanoparticles: Synthesis, Optimization, and Differential Binding to Influenza Hemagglutinins

Abstract

During influenza infection, hemagglutinins (HAs) on the viral surface bind to sialic acids on the host cell’s surface. While all HAs bind sialic acids, human influenza targets terminal α2,6 sialic acids and avian influenza targets α2,3 sialic acids. For interspecies transmission (zoonosis), HA must mutate to adapt to these differences. Here, multivalent gold nanoparticles bearing either α2,6- or α2,3-sialyllactosamine have been developed to interrogate a panel of HAs from pathogenic human, low pathogenic avian, and other species’ influenza. This method exploits the benefits of multivalent glycan presentation compared to monovalent presentation to increase affinity and investigate how multivalency affects selectivity. Using a library-orientated approach, parameters including polymer coating and core diameter were optimized for maximal binding and specificity were probed using galactosylated particles and a panel of biophysical techniques [ultraviolet–visible spectroscopy, dynamic light scattering, and biolayer interferometry]. The optimized particles were then functionalized with sialyllactosamine and their binding analyzed against a panel of HAs derived from pathogenic influenza strains including low pathogenic avian strains. This showed significant specificity crossover, which is not observed in monovalent formats, with binding of avian HAs to human sialic acids and vice versa in agreement with alternate assay formats. These results demonstrate that precise multivalent presentation is essential to dissect the interactions of HAs and may aid the discovery of tools for disease and zoonosis transmission.

The SARS-COV-2 Spike Protein Binds Sialic Acids and Enables Rapid Detection in a Lateral Flow Point of Care Diagnostic Device

“…This switch in glycan specificity has enabled the establishment of glycan-functional biosensors to rapidly identify strains without using nucleic acid based detection methods. 18 , 19 All coronaviruses display homotrimers of spike glycoproteins on their surface. Sialic acid binding by the S1 spike protein subunits is crucial for coronavirus to engage host cells, while the S2 domain initiates viral fusion.…”

The SARS-COV-2 Spike Protein Binds Sialic Acids, and Enables Rapid Detection in a Lateral Flow Point of Care Diagnostic Device

“…Due to the cluster glycoside effect, 28 displaying multiple copies of glycans can result in several orders of magnitude enhancement in the observed affinity. This has been widely exploited in materials chemistry 29,30 using dendrimers, 31,32 peptides/proteins, 33 polymers, 34,35 and nanoparticles 19,36 to generate high avidity.…”

The SARS-COV-2 Spike Protein Binds Sialic Acids, and Enables Rapid Detection in a Lateral Flow Point of Care Diagnostic Device

“…Dh(UV) (c) (nm) 18 to replicate a lateral flow situation, which is the primary aim of this work. Since there are 22 N-linked glycans per protein which are not present in bacteria-expressed protein, 39 we used protein expressed in mammalian cells (HEK) to ensure glycosylation.…”