Antimicrobial Nonisocyanate Polyurethane Foam Derived from Lignin for Wound Healing

Abstract

Medical dressings, as a cover for wounds, can replace damaged skin in the wound healing process to play a temporary barrier role, avoid or control wound infection, and provide a favorable environment for wound healing. Therefore, there is an urgent need for medical antimicrobial dressings for the treatment of chronic wounds. Although traditional polyurethane foam has been widely used in medical dressings, conventional polyurethane foams are primarily prepared using nonbiocompatible isocyanate-based compounds, which are potentially hazardous for both operators and applications in the medical field. Here, we propose nonisocyanate polyurethane foams naturally derived from lignin by enzymatic lignin alkylation, cyclic carbonation modification, and polymerization with diamine and the addition of a blowing agent. Silver nanoparticle solution was added during foaming to confer antimicrobial properties. This lignin-based nonisocyanate polyurethane/silver composite foam (named NIPU foam-silver) using a green synthesis method has good mechanical properties, which can be used to manufacture polyurethane/silver foams, and thermal and antimicrobial properties. Notably, NIPU foam-Ag showed more than 95% bactericidal efficacy against both Escherichia coli and Staphylococcus aureus within 4 h. Evaluation of in vitro wounds in mice showed that this antimicrobial composite foam rapidly promotes wound healing and repairs damaged tissue. This suggests that this biobased biodegradable antimicrobial foam has significant scope for clinical applications in wound management.

Spatiotemporally Controllable Bifunctional Micellar-Carbon Dot Supernanoparticles for Wounds Healing

“…The indiscriminate use of antibiotics contributes to a relentless surge in bacterial resistance, potentially pushing humanity into a scenario where “no drugs are available”, thereby intensifying the challenges of treating infected wounds. − Antibacterial photodynamic therapy (aPDT) has garnered increasing attention as a light-controllable, rapid, efficient, noninvasive, and broad-spectrum antimicrobial strategy for addressing infected wounds. ,− In the aPDT process, photosensitizers activated by specific wavelengths swiftly produce a multitude of reactive oxygen species (ROS), − capable of directly impairing bacterial cell walls, membranes, lipids, and nucleic acids, thereby accomplishing antimicrobial effects. ,− This antibiotic-free therapy notably mitigates the likelihood of antibiotic-resistant bacteria. ,, However, despite the potent bactericidal efficacy demonstrated by aPDT through the induction of ROS generation, its side effect of localized ROS overdose, resulting in increased inflammation and tissue damage, has not been adequately addressed. , …”