Polymer/silver hybrid thin films for anti-pathogenic bacterial applications Available to Purchase

Gold (Au)- and indium-tin-oxide (ITO)-coated glass plates grafted with polymer/silver nanoparticle (Ag NP) hybrid coatings were prepared and served as biocidal surfaces directed against two biofilm-positive bacteria, namely Listeria monocytogenes ATCC 19115 and Staphylococcus aureus ATCC 25923. The polymer films were prepared by surface-initiated radical photopolymerisation of methacrylic acid (MAA) and 2-hydroxyethyl methacrylate (HEMA) in the presence of Au or ITO surfaces grafted with photoinitiator groups from diazotised benzophenone or N,N-dimethylaminobenzenediazonium tetrafluoroborate (N₂C₆H₄N(CH₃)₂BF₄). The Ag NPs were generated in situ on the polymer surfaces by reduction of silver nitrate. The degree of biofilm formation by L. monocytogenes ATCC 19115 and S. aureus ATCC 25923 strains on these surfaces was evaluated. Viable attached cells were quantified using a colorimetric method based on the ability of viable attached cells to metabolically reduce 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide to a formazan dye. This study shows that diazonium salts permit to anchor robust hydrophilic coatings with immobilised Ag NPs of remarkable antifouling properties against pathogenic S. aureus and L. monocytogenes bacteria: antifouling due to both hydrophilic MAA and/or HEMA repeat units, and bactericidal due to the Ag NPs complexed by the COOH groups from MAA repeat units.