Multi-Functional Polyurethane Hydrogel Foams with Tunable Mechanical Properties for Wound Dressing Applications

Polyurethane hydrogel foams synthesized through a facile one-pot, solvent-free process are described. The roles of polyethylene glycol (PEG) molecular weight, crosslinking density, and foam stabilizer concentration on polymer properties are evaluated for potential applications as wound dressing materials. Material characterization and wound dressing relevant performance evaluations are performed to understand effects of individual components and identify promising formulations. Surprisingly for a solvent-free reaction, complete polymerization is confirmed by IR and gel fraction analyses. Foam stabilizing agent loading increases mechanical properties including Young's modulus, extensibility, and toughness while decreasing pore size and drug release rate. Mechanical properties are also dependent on the crystalline melting temperature of the PEG diol. Utilizing caffeine as a drug surrogate, high performance liquid chromatography (HPLC) drug-release analysis identifies that polyurethane hydrogel foams exhibit initial burst release kinetics followed by sustained release over 24 h. Antibiotic compatibility and release is demonstrated for all formulations by zone of inhibition testing against gram-positive and negative bacteria.