Effectiveness of the Nanosilver/TiO₂-Chitosan Antiviral Filter on the Removal of Viral Aerosols

Abstract

Background: The precaution of airborne transmission of viruses, such as influenza, SARS, MERS, and COVID-19, is essential for reducing infection. In this study, we applied a zero-valent nanosilver/titania-chitosan (nano-Ag 0 /TiO 2 -CS) filter bed, whose broad-spectrum antimicrobial efficacy has been proven previously, for the removal of viral aerosols to minimize the risk of airborne transmission. Methods: The photochemical deposition method was used to synthesize the nano-Ag 0 /TiO 2 -CS antiviral material. The surface morphology, elemental composition, and microstructure of the nano-Ag 0 /TiO 2 -CS were analyzed by a scanning electron microscopy/energy dispersive X-ray spectroscopy and a transmission electron microscopy, respectively. The MS2 bacteriophages were used as surrogate viral aerosols. The antiviral efficacy of nano-Ag 0 /TiO 2 -CS was evaluated by the MS2 plaque reduction assay (PRA) and filtration experiments. In the filtration experiments, the MS2 aerosols passed through the nano-Ag 0 /TiO 2 -CS filter, and the MS2 aerosol removal efficiency was evaluated by an optical particle counter and culture method. Results and Conclusions: In the MS2 PRA, 3 g of nano-Ag 0 /TiO 2 -CS inactivated 97% of MS2 bacteriophages in 20 mL liquid culture (2 -0.5 • 10 16 PFU/mL) within 2 hours. The removal efficiency of nano-Ag 0 /TiO 2 -CS filter (thickness: 6 cm) for MS2 aerosols reached up to 93%. Over 95% of MS2 bacteriophages on the surface of the nano-Ag 0 /TiO 2 -CS filter were inactivated within 20 minutes. The Wells-Riley model predicted that when the nano-Ag 0 /TiO 2 -CS filter was used in the ventilation system, airborne infection probability would reduce from 99% to 34.6%. The nano-Ag 0 /TiO 2 -CS filter could remain at 50% of its original antiviral efficiency after continuous operation for 1 week, indicating its feasibility for the control of the airborne transmission.

Surface modification of TiO2 nanoparticles with organic molecules and their biological applications

“…Wang et al successfully tested the antiviral efficacy of TiO 2 –chitosan (CS) –AgNP filter for viral aerosols and reported the infection risk reduction and long-term antiviral efficacy of this nanosystem. 267 In this study, the TiO 2 –CS–AgNP filter was synthesized for the removal and deactivation of airborne MS2 bacteriophage particles. In the air purification system, their results showed a 93% removal of the airborne MS2 particles, and more than 95% of MS2 can be efficiently deactivated on the surface of this nanosystem within 20 minutes.…”

Anti-COVID-19 Credentials of Chitosan Composites and Derivatives: Future Scope?

“…In an inflammatory context, HPD/NPs demonstrated higher cellular absorption in vitro and in vivo compared to HPD alone. In a mouse model, HPD/NPs greatly reduced lung damage by decreasing the levels of pro-inflammatory cytokines and decreased vascular permeability [ 164 ].…”

Photocatalytic TiO2 nanomaterials as potential antimicrobial and antiviral agents: Scope against blocking the SARS-COV-2 spread

“…Wang et al [ 99 ] developed antimicrobial zero-valent nanosilver/titania-chitosan (nano-Ag 0 -TiO 2 -CS) filter bed for the removal and deactivation of airborne MS2 bacteriophage particles (viral aerosols). It was found that these composite systems were very effective for removing 93% of airborne MS2 particles and more than 95% of the MS2 could be efficiently deactivated in 20 min while using in an air purification system.…”