Water-Soluble Sulfur-Ylide-Functionalized Polyacrylamides for Antibacterial Surface Applications

Surface fouling induced by biomolecules and microorganisms remains a persistent challenge in materials science, particularly in healthcare applications, where biofilm formation on medical devices may lead to infections and antimicrobial resistance. Antifouling strategies typically rely on the formation of either hydration layers or cytotoxic materials for direct antimicrobial effects. Recent advances in zwitterionic polymers derived from ylides offer a promising yet unexplored toolbox for the construction of antifouling and antimicrobial coatings. While N-oxide-based ylides have been extensively studied as building blocks for antifouling materials, sulfur-ylide-based materials, and the precise underlying mechanisms remain underexplored despite their broader chemical versatility. Here, we present a fully water-soluble acrylamide-based poly(sulfur ylide) and compare its properties to those of previously reported hydrophobic polystyrene-derived analogues. Notably, water-soluble poly(sulfur ylides) retain antimicrobial efficacy on surfaces but lose cytotoxicity in solution, unlike its hydrophobic counterpart. Computational studies reveal that the dipole moment of sulfur ylides is environmentally responsive, stabilizing in hydrophobic environments. Genetic analysis confirms outer membrane destabilization for both polymers but suggests that the hydrophobicity of the polystyrene backbone promotes stronger interactions. We suggest that future work should focus on elucidating additional interactions, including supramolecular behaviors of amphiphilic sulfur ylides, to refine their structure–property relationships and optimize their antifouling and antimicrobial properties.