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Reactive oxygen species–degradable polythioketal urethane foam dressings to promote porcine skin wound repair

Porous, resorbable biomaterials can serve as temporary scaffolds that support cell infiltration, tissue formation, and remodeling of nonhealing skin wounds. Synthetic biomaterials are less expensive to manufacture than biologic dressings and can achieve a broader range of physiochemical properties, but opportunities remain to tailor these materials for ideal host immune and regenerative responses. Polyesters are a well-established class of synthetic biomaterials; however, acidic degradation products released by their hydrolysis can cause poorly controlled autocatalytic degradation. Here, we systemically explored reactive oxygen species (ROS)–degradable polythioketal (PTK) urethane (UR) foams with varied hydrophilicity for skin wound healing. The most hydrophilic PTK-UR variant, with seven ethylene glycol (EG7) repeats flanking each side of a thioketal bond, exhibited the highest ROS reactivity and promoted optimal tissue infiltration, extracellular matrix (ECM) deposition, and reepithelialization in porcine skin wounds. EG7 induced lower foreign body response, greater recruitment of regenerative immune cell populations, and resolution of type 1 inflammation compared to more hydrophobic PTK-UR scaffolds. Porcine wounds treated with EG7 PTK-UR foams had greater ECM production, vascularization, and resolution of proinflammatory immune cells compared to polyester UR foam–based NovoSorb Biodegradable Temporizing Matrix (BTM)–treated wounds and greater early vascular perfusion and similar wound resurfacing relative to clinical gold standard Integra Bilayer Wound Matrix (BWM). In a porcine ischemic flap excisional wound model, EG7 PTK-UR treatment led to higher wound healing scores driven by lower inflammation and higher reepithelialization compared to NovoSorb BTM. PTK-UR foams warrant further investigation as synthetic biomaterials for wound healing applications. Description Hydrophilic polythioketal urethane foam scaffolds promote skin wound healing in pigs. Designing degradable dressings Synthetic scaffolds are an attractive option for dressings to treat skin wounds because they are shelf stable, have tunable and defined chemical compositions, and are more affordable than naturally derived scaffolds or cell-based dermal substitutes. Here, Patil and colleagues investigated the role of scaffold hydrophilicity in polythioketal-based polyurethane (PTK-UR) foam scaffold resorption and promotion of tissue regeneration in wound healing. They found that hydrophilic scaffolds with seven ethylene glycol units between the thioketal bonds in the polymer backbone exhibited optimal reactive oxygen species–dependent degradation and porcine skin wound healing, including ischemic flap excisional wounds. Results support further investigation of PTK-UR formulations as alternatives to commercially available wound matrices.