Multivalent-copper-loaded layer-by-layer coating for antibacterial and instantaneous virucidal activity for protective textiles

Abstract

Nanoarchitectured films are known for tailoring surface properties, while antimicrobial surfaces can reduce pathogen propagation in public spaces and on protective equipment. This study explores the layer-by-layer (LbL) method to create antiviral and antibacterial surfaces against disease transmission. Chitosan and carboxymethylcellulose films were assembled using LbL to incorporate ionic copper, a broad-spectrum antimicrobial agent, onto textile substrates, such as those used in furnishings and personal protective equipment. Film assembly conditions favored the conversion of Cu(II) into multivalent copper, immediately inactivating the MHV-3 virus, Gram-negative (E. coli), and Gram-positive (S. aureus) bacteria. Mechanical tests demonstrate that copper ions have a low impact on the coating and textile physical properties, such as elasticity, tensile strength, and film roughness, by promoting ionic crosslinking of chitosan in the film, while the coating kept air permeability. The coating hydrophilicity and copper release profile were also tuned by the deposition of additional hydrophobic barriers, such as L-alpha-phosphatidylcholine phospholipid or polydimethylsiloxane (PDMS) by spin-coating or plasma polymerization, respectively. Viral inactivation is achieved by the local release of copper ions in contaminated droplets. The coating may also act as a droplet-absorbing barrier, demonstrating the potential of these films for enhancing pathogen resistance and infection control in textile surfaces.