Physical, morphological, and wound healing properties of a polyurethane foam-film dressing

Background: We investigated the physicochemical properties of $Medifoam^{(R)}$ N and its wound healing performance compared to other commercially available polyurethane (PU) foam dressing in vitro and in vivo to gain insight in their clinical performance. Methods: Wound contact layer and cross-section of eleven polyurethane foam dressings were assessed with field-emission scanning electron microscope. Thickness, density, tensile strength, elongation, moisture-vapor transmission rate (MVTR), retention and absorptivity were measured to compare physical properties. Phosphate-buffered saline (PBS) solution absorption patterns were compared. An animal model for wound-healing was applied to validate in vitro findings. Results: Among eleven tested foam dressings, $Medifoam^{(R)}$ N has the smallest pore and cell sizes with excellent uniformity, i.e. it has $25{\sim}75{\mu}m$ on the wound contact layer and $100{\sim}350{\mu}m$ in the cross-section while other dressings have a larger pose size with larger variability. Compared to other PU foams, $Medifoam^{(R)}$ N also has moderate thickness, density, tensile strength, elongation and MVTR. Furthermore, it has excellent fluid absorption and retention capacity. These intrinsic properties of $Medifoam^{(R)}$ N contributed to improve fluid absorption patterns, i.e. other dressing material flawed out PBS solution on the dressings while $Medifoam^{(R)}$ N retained all the tested solutions. In animal wound-healing study, $Medifoam^{(R)}$ N treated animals showed excellent angiogenesis and collagen deposition even though epithelial recovery rate was not significantly different to other dressings. Conclusions: $Medifoam^{(R)}$ N has optimized physical properties and thus improved fluid absorption/retention capacity. Compared to other dressings, $Medifoam^{(R)}$ N showed excellent fluid absorption patterns and these characteristics contributed to improved wound healing and excellent angiogenic potential. We found that $Medifoam^{(R)}$ N showed the best results among the employed dressing samples.