Nanomaterials have the characteristics associated with high surface-to-volume ratios and have been explored for their
antiviral activity. Despite some success, cytotoxicity has been an issue in nanomaterial-based
antiviral strategies. We previously developed a novel method to fully exfoliate
montmorillonite clay to generate the most fundamental units of nanoscale
silicate platelet (NSP). We further modified NSP by capping with various
surfactants and found that the
surfactant-modified NSP (NSQ) was less cytotoxic. In this study, we tested the
antiviral potentials of a series of natural-
clay-derived nanomaterials. Among the derivatives, NSP modified with anionic
sodium dodecyl sulfate (NSQc), but not the pristine
clay, unmodified NSP, a
silver nanoparticle-NSP hybrid, NSP modified with cationic n-octadecanylamine hydrochloride
salt, or NSP modified with nonionic
Triton X-100, significantly suppressed the plaque-forming ability of Japanese encephalitis virus (JEV) at noncytotoxic concentrations. NSQc also blocked
infection with dengue virus (DEN) and influenza A virus. Regarding the
antiviral mechanism, NSQc interfered with viral binding through electrostatic interaction, since its
antiviral activity can be neutralized by
Polybrene, a cationic
polymer. Furthermore, NSQc reduced the lethality of JEV and DEN
infection in mouse challenge models. Thus, the
surfactant-modified exfoliated nanoclay NSQc may be a novel nanomaterial with broad and potent
antiviral activity.
IMPORTANCE: Nanomaterials have being investigated as
antimicrobial agents, yet their
antiviral potential is overshadowed by their cytotoxicity. By using a novel method, we fully exfoliated
montmorillonite clay to generate the most fundamental units of nanoscale
silicate platelet (NSP). Here, we show that the
surfactant-modified NSP (NSQ) is less cytotoxic and that NSQc (NSP modified with
sodium dodecyl sulfate) could potently block
infection by dengue virus (DEN), Japanese encephalitis virus (JEV), and influenza A virus at noncytotoxic concentrations. For the
antiviral mechanism, we find that the electrostatic interaction between the negatively charged NSQc and the positively charged virus particles blocks viral binding. Furthermore, we used mouse challenge models of JEV and DEN to demonstrate the in vivo
antiviral potential of NSQc. Thus, NSQc may function as a potent and safe
antiviral nanohybrid against several viruses, and our success in synthesizing
surfactant-modified NSP with
antiviral activity may shed some light on future
antiviral development.