NIR-responsive waterborne polyurethane-polydopamine coatings for light-driven disinfection of surfaces

Apart from conventional chemical-based methods, alternative disinfection methods that can physically destroy bacteria are needed. Here, biocompatible, non-toxic, environmentally friendly hybrid coatings prepared from dispersions of polydopamine-coated waterborne polyurethane particles (WPU-PDA) that offer effective light-to-heat conversion were designed to eradicate pathogenic bacteria and biofilms using photothermal therapy. The resulting WPU-PDA hybrid coatings demonstrated an effective photothermal activity by reaching 155 °C under 4 min NIR-laser irradiation and staying stable upon multiple irradiation cycles. WPU-PDA coatings induced hyperthermia on S. aureus resulting in a 3.5 log reduction of viable cells with a killing activity that is stable for at least 20 contamination/disinfection cycles. Furthermore, the prepared coatings were shown to have antibiofilm properties resulting in a 3 min NIR-light activated 3.9 log reduction in the viability through physical disruption of biofilm bacteria. Light-activated antibacterial/antibiofilm coatings demonstrated here provide a strong potential for NIR-light activated disinfection of surfaces.