# Silver Nitrate and Bioactive Glass Containing Chitosan Coatings: Comparison of Antimicrobial and Antiviral Properties

## TL;DR

This paper compares chitosan-based coatings with silver nitrate or bioactive glass to enhance filters' ability to kill bacteria and viruses.

## Contribution

The study introduces and evaluates novel chitosan-based antimicrobial coatings for filters with broad-spectrum pathogen inactivation.

## Key findings

- Chitosan/AgNO3 and chitosan/BG coatings maintained filter pore integrity and filtration capability.
- Both coatings showed >99% antibacterial activity against Staphylococcus aureus.
- Chitosan/BG coatings were active against all tested respiratory viruses, while chitosan/AgNO3 was partially effective.

## Abstract

Pathogenic air and water contaminations present major
health issues
nowadays. Filter-based protective devices have been commonly utilized
to capture airborne or waterborne microorganisms and viruses in order
to reduce or inhibit the transmission of infectious diseases. Some
approaches to extend the functionality of filtering devices and to
further enhance their capability to inactive pathogens include the
application of antimicrobial coatings on the filter surface. In this
regard, the current work aims to develop innovative coatings with
antiviral and antibacterial properties composed of a chitosan matrix
incorporating bioactive glass (BG) nanoparticles or silver nitrate
(AgNO3) on metallic filters by using electrophoretic deposition.
The so-produced chitosan/BG- and chitosan/AgNO3-coated
filters were characterized in terms of their morphology, chemical
composition, filtering capability, antibacterial properties against Staphylococcus aureus, and antiviral activity against
coronavirus OC43, rhinovirus, adenovirus, and influenza virus. The
results confirmed that chitosan/AgNO3 and chitosan/BG coatings
exhibited no blockage of the filter pores. The bubble point values
for both coating types were similar to the measurements of uncoated
filters, suggesting intact filtration capability after the application
of the coatings. The antibacterial assay showed the antibacterial
activity of >99% for both chitosan/AgNO3 and chitosan/BG
coatings against S. aureus. Finally,
chitosan/AgNO3-coated filters showed antiviral activity
against three out of the four tested viruses (HCoV-OC43, HRV-A1, and
IFV-AH3N2) and exerted a partial antiviral action against AdV-5. On
the other hand, chitosan/BG-coated filters were active against all
tested respiratory viruses. The outcomes of this study evidenced that
the developed multimaterial coatings could serve as a suitable platform
to produce antimicrobial filtering systems for a broad-spectrum application.