Antibacterial hybrid coatings from halloysite-immobilized lysostaphin and waterborne polyurethanes

Abstract

Lysostaphin enzyme is an effective antibacterial agent proven to be promising for the prevention of healthcare-associated infections related to methicillin-resistant Staphylococcus aureus (MRSA). Here, safe, and non-toxic antibacterial hybrid coatings consisting of lysostaphin and waterborne polyurethane (PU) are presented. Lysostaphin was covalently immobilized onto polydopamine functionalized halloysite nanotubes (HNTs) to obtain stable HNT-lysostaphin nanohybrid structures with high effective lysostaphin concentrations, which were then incorporated into PU coatings by a facile spray coating process. Resulting PU/HNT-lysostaphin hybrid coatings presented strong antibacterial activity against S. aureus with a >99 % killing efficiency. The incorporation of lysostaphin into the polymer matrix via HNTs as a carrier enhanced the stability of the enzyme resulting in non-leaching coatings that presented high operational stability over multiple bacterial incubation cycles and high storage stability without any significant loss of enzymatic activity. Furthermore, PU/HNT-lysostaphin coatings demonstrated significant antibiofilm properties and reduced the formation of S. aureus biofilms by 70 % relative to neat PU coatings. The lysostaphin based antibacterial hybrid coatings developed in this study, which can be easily applied to surfaces in healthcare facilities and medical devices offer an effective approach for the prevention of S. aureus associated nosocomial infections.