Urushiol-acrylate terpolymers: Synthesis, characterization, and antibacterial effects against Staphylococcus aureus

A series of non-leaching urushiol-containing acrylate terpolymers were synthesized and assessed against Staphylococcus aureus. Compositional heterogeneity of the polymer backbone was predicted owing to the diverse chemical nature of the monomers: 2-hydroxyethylacrylate (HEA), 2-methoxyethylacrylate (MEA), methyl methacrylate (MMA), acrylic acid (AA), and urushiol (U). A variety of surface-driven properties of the terpolymer matrices, such as hydrophilicity, hydrophobicity, and amphiphilicity, are assumed to obstruct nonspecific protein adsorption on the substrate, thereby preventing further microbial adhesion and colonization. Four sets of terpolymers were prepared and fabricated into films: poly(HEA-U-MEA), poly(HEA-U-MMA), poly(HEA-U-AA), and poly(MEA-U-AA), which are represented as poly(R₁-U-R₂), where R₁ and R₂ represent HEA/MEA/MMA/AA, and U represents urushiol. Spin-cast polymers were subjected to antibacterial assessment against a methicillinresistant strain of Staphylococcus aureus. The terpolymers demonstrated excellent antimicrobial responses against S. aureus, as measured using the fluorescent dyes 5-cyano-2,3-ditolyl tetrazolium chloride and 4',6- diamidino-2-phenylindole. Physicospectroscopic techniques such as nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis, and confocal laser scanning microscopy were employed to investigate the polymers.