Vegetable oil-based polyurethanes as antimicrobial wound dressings: in vitro and in vivo evaluation

Preparation of efficient polyurethane-type wound dressings with tunable physicomechanical properties and widespread antimicrobial activity is considered in this work. A new type of soybean oil-based polyol with built-in urethane and quaternary ammonium groups is synthesized through a nonisocyanate route using carbonated soybean oil as an environmentally friendly, renewable resource-based raw material. Different formulations from this polyol and castor oil are prepared and converted to the polyurethane wound dressings via a reaction with isophorone diisocyanate. The dressing sample, with good cytocompatibility and efficient antimicrobial activity against various microbial strains, having tensile strength of 5 and 17 MPa at hydrated and dry state, elongation at the break of up to 400%, equilibrium water absorption and a water vapor transmission rate of 50% and 390 g m^-2 day^-1, is used for in vivo assay on a rat. Evaluation of the optimized dressing for a full-thickness non-sterilized wound has shown excellent progress of wound healing, since the tensile strength of regenerated skin reaches about 80% of normal healthy skin on day 21 after wounding. This has been significantly superior to the tensile strength of the regenerated skin of rats covered with non-antibacterial (∼50%) and cotton gauze (∼40%) dressings as blank and control groups.