Integrated Endotoxin Adsorption and Antibacterial Properties of Cationic Polyurethane Foams for Wound Healing

Gram-negative bacteria, containing toxic proinflammatory and pyrogenic substances [endotoxin or lipopolysaccharide (LPS)], can lead to infection and associated serious diseases, such as sepsis and septic shock. Development of antimicrobial materials with intrinsically endotoxin adsorption activity can prevent the release of bacterial toxic components while killing bacteria. Herein, a series of imidazolium-type polyurethane (PU) foams with antimicrobial properties were synthesized. The content effects of cationic moieties on the antimicrobial activities against Gram-negative Escherichia coli and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus as well as the endotoxin adsorption property were investigated. The obtained PU foams show slightly higher efficiency against two Gram-negative strains than for Gram-positive one and high absorbability of LPS. A wound healing test using P. aeruginosa and its isolated LPS-treated mice as the models further demonstrated that imidazolium-type PU foams combine both antibacterial and endotoxin adsorption properties and may have a potential application as an antimicrobial wound dressing in a clinical setting.