are used to mimic cell surfaces and favor the interaction between the particles and the capsid. In particular, sulfonates and organic sulfates have been used for their capacity to attract the virus via capsid protein interaction and block the HA activity.41 AuNPs functionalized with sulfonates showed an increasing inhibition of influenza A compared to the nanoparticles capped with succinic acid.42 This study also demonstrated that there is not a correlation bet