Seasonal influenza causes thousands of human deaths each year. However, of particular concern is the threat of a pandemic caused by the influenza virus crossing between animal species. Measures to prevent an influenza virus pandemic involve vaccination and antiviral drugs, the latter ideally administered within 48h of infection. The effective use of antivirals requires rapid and early diagnosis. Current methods for the detection of influenza are time-consuming and require trained analysts and specialised equipment. Our research is aimed at the development of a colorimetric test for the rapid detection and discrimination between human and avian influenza virus based on gold nanoparticles (AuNPs) functionalised with carbohydrate-based ligands (glyconanoparticles). Surfaces of human and avian influenza viruses are covered by carbohydrate receptors haemagglutinin (HA). These receptor proteins are slightly different in human and avian influenza viruses resulting in preferential binding to sialic acid α2,6- and α2,3-galactose sequences, respectively. To date, we have functionalised gold nanoparticles (AuNPs, ca. 16 nm in diameter) with bespoke sialic acid α2,6-galactose-based ligands which show high specificity to human HA. In aqueous solution AuNPs exhibit an intense red colour due to their surface plasmon absorption band. In the presence of a human influenza virus (H3N2), the ligand on the glyconanoparticles binds to the haemagglutinin on the virus inducing the aggregation of the nanoparticles causing the colour change of their solution. The detection of human influenza virus using the designed system was achieved by the naked eye within 30 min. To date, we have developed an influenza test that is simple and quick, and importantly, is able to distinguish between seasonal influenza and animal strains, presenting significant advantages over existing methods of detection. Our bioassay has a competitive advantage over existing methods for the detection of influenza virus since it can simultaneously detect and discriminate between human and avian influenza.
Schematic representation of the aggregation of the glyconanoparticles in the presence of influenza virus. The sialic acid-containing ligand on the surface of gold naonoparticles binds to haemagglutinin (HA) on the surface of the virus inducing aggregation.
The current research, which completes the already developed technology, focuses on the synthesis of glyconanoparticles that provide a positive outcome for avian flu virus detection. More importantly, we are working on the development of the portable product suitable for point-of care.
This work is carried out in collaboration with Prof. David Russel and Maria J. Marin from the University of East Anglia (UEA, Norwich).
Marin, M. J.; Schofield, C. L.; Field, R. A.; Russell, D. A., Glyconanoparticles for colorimetric bioassays. Analyst2015, 140 (1), 59-70.
Marin, M. J.; Rashid, A.; Rejzek, M.; Fairhurst, S. A.; Wharton, S. A.; Martin, S. R.; McCauley, J. W.; Wileman, T.; Field, R. A.; Russell, D. A., Glyconanoparticles for the plasmonic detection and discrimination between human and avian influenza virus. Org. Biomol. Chem. 2013, 11 (41), 7101-7107.