AuNPs/graphene Hybrids-Based Enzyme-Free Plasmonic Immunoassay for Respiratory Syncytial Virus Detection

Accurate diagnosis of early infections caused by the viral pathogen is a major challenge because patients usually have nonspecific signs. The development of sensitive, reliable, robust, and rapid laboratory tools is still in high demand. Herein, we developed an extremely sensitive and affordable plasmonic immunoassay for respiratory syncytial virus (RSV) detection with the naked eye based on gold nanoparticles (AuNPs)/graphene hybrids combined with metal enhancement solution. The limit of detection was found to be 1.7 fg/mL, which was 100 times higher than that of the AuNPs-based method. The ultrahigh sensitivity could be attributed to the large number of well-dispersed AuNPs deposited on the graphene surface, which had an extremely high relative surface area. Further signal amplification was achieved by catalytic enlargement of AuNPs with HAuCl4-NH2OH redox reaction. Moreover, the plasmonic immunoassay was successfully used to detect RSV in artificial serum samples, showing great potential in practical applications.