Multivalent Sialyllactose-Levan-Conjugated Gold Nanoparticles for Efficient Interaction with and Colorimetric Detection of Influenza A Virus

We report a colorimetric assay to detect influenza A virus using sialyllactose-levan-conjugated gold nanoparticles (AuNPs). We successfully conjugated 2, 3- and 2, 6-sialyllactose to levan and synthesized sialyllactose-levan-conjugated AuNPs. Each sialyllactose-conjugated levan specifically interacted with a recognizable lectin. Synthesized sialyllactose-conjugated levan acted as reducing and coating agents during the formation of AuNPs. Human influenza A virus specifically bound to 2, 6-sialyllactose-levan-conjugated AuNPs. Moreover, 2, 6-sialyllactose-conjugated levan AuNPs rapidly changed color from red to blue after incubation with human influenza virus. For detecting avian influenza virus, 2, 3-sialyllactose-levan-conjugated AuNPs were more effective than 2, 6-sialyllactose-levan-conjugated AuNPs. Therefore, the efficient targeting and diagnosis of influenza virus according to origin was possible. The deployment of sialyllactose-levan-conjugated particles for the detection of influenza virus is simple and quick. The limit of detection (L.O.D) of H1N1 influenza virus was 7.4 × 103 pfu using 2, 6-siallylactose-levan-conjugated AuNPs and H5N2 influenza virus was 4.2 × 103 pfu using 2, 3-siallylactose-levan- conjugated AuNPs.