Ag_xO_y/chitosan nanocomposite as antibacterial functional coating material for hydrophilic and hydrophobic fabrics

The applications of antibacterial fabrics extend over a range from daily wear to defence wear. In this regard, the present work emphasises the development of a coating mixture that can impart antibacterial activity regardless of the wetting ability of the fabric. Here, nano Ag/Ag₃O₄/chitosan (n-Ag/Ag₃O₄/CH) was prepared using one pot method and utilized as an antibacterial coating mixture for hydrophilic cotton and hydrophobic Nomex fabrics. TEM analysis confirmed near-spherical nanoparticles with sizes of 5 nm -10 nm embedded in the chitosan matrix. Antibacterial evaluation revealed a minimum inhibitory concentration of 36 μg/mL for Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA), and 75 μg/mL for Staphylococcus epidermidis (S. epidermidis). The coated fabrics exhibited inhibition zones of 0.5 cm - 0.7 cm against E. coli, 0.1 cm against S. epidermidis, and 0.3-0.5 cm against MRSA (AATCC-147 method) for both cotton and Nomex fabrics. Quantitative results from the AATCC-100 assay showed a ∼ 100 % reduction in bacterial colonies for all three strains. Notably, the n-Ag/Ag₃O₄/CH coatings remained effective even after 50 washing cycles and abrasion tests, confirming good durability. Zebrafish behavioural assays revealed significant alterations, including reduction in average swimming speed and a shift in zone preference, although social interaction remained unaffected. These findings demonstrate that n-Ag/Ag₃O₄/CH coatings can impart durable antibacterial properties to both hydrophilic and hydrophobic fabrics, though further studies are required to minimize environmental effects before commercial application.