Polysiloxane-based polyurethane/quaternary ammonium-zwitterionic pressure-sensitive adhesive composite double dressing with antimicrobial and antifouling properties

The development of wound dressings that combine mechanical strength, flexibility, biocompatibility, and multifunctionality continues to pose significant challenges in biomedical engineering. This study introduces an innovative bilayer polyurethane composite dressing featuring distinct functional layers. The polyurethane protective layer (PUPL), fabricated from polydimethylsiloxane-based polyurethane, functions as a hydrophobic, mechanically robust barrier that simultaneously provides structural integrity, flexibility, and effective protection against fluid penetration and environmental contaminants, thereby minimizing external interference with the wound healing process. The polyurethane functional layer (PUFL) comprises cationically and zwitterionically modified polyurethane pressure-sensitive adhesives, engineered to exhibit optimal differential adhesion properties in both wet and dry conditions along with multifunctional characteristics. This modification strategy harnesses the antimicrobial efficacy of cationic polymers while mitigating potential wound inflammation through zwitterionic ions that reduce cation-induced protein adsorption. Furthermore, incorporating polyethylene glycol into the polyurethane pressure-sensitive adhesive's soft segment enhances the material's hydrophilicity and moisture retention capacity, promoting an optimal moist wound healing environment. The resulting bilayer dressing demonstrates superior mechanical properties, excellent flexibility, and appropriate water vapor transmission rates, enabling secure wound adhesion. Moreover, it exhibits remarkable biocompatibility along with pronounced antimicrobial and antifouling capabilities. The synergistic interaction between the hydrophobic protective layer and the functional adhesive layer offers a promising platform for advancing next-generation wound healing materials.