Abstract
COVID-19 disease, triggered by SARS-CoV-2 virus infection, has led to more than 7.0 million deaths worldwide, with a significant fraction of recovered infected people reporting postviral symptoms. Smart surfaces functionalized with nanoparticles are a powerful tool to inactivate the virus and prevent the further spreading of the disease. Literature reports usually focus on the role of nanomaterial composition and size dispersion in evaluating their efficacy against SARS-CoV-2. Here, the anti-SARS-CoV-2 activity of oleylamine (OAm) used as a capping agent of silver nanoparticles is quantified for the first time. Spherical hydrophobic nanoparticles with 8 ± 2 nm diameter were prepared and characterized by Fourier transform infrared, dynamic light scattering, and transmission electron microscopy techniques. Biological assays showed that microgram amounts of nanoparticles, deposited on nonwoven textile obtained from surgical masks, efficiently inactivated up to 99.6(2)% of the virus with just 2 min of exposure. The virucidal activity of the corresponding amount of free OAm has been determined as well, reaching up to 67(1)% of activity for an exposure time of 10 min. Inductively coupled plasma optical emission spectrometry results pointed out a low leaching out of the nanoparticles in contact with water or culture medium. All in all, these results propose the capping molecules as an important chemical variable to be taken into account in the design of fast, efficient, and long-lasting anti-SARS-CoV-2 coatings.