A Hydrophilic Polyurethane Foam Containing Nigella sativa Oil as a Wound Dressing

Some challenges with current wound dressings include limited availability of advanced options and antimicrobial effectiveness. Polyurethane (PU) foams could be suitable choices as wound dressings once their disadvantages are resolved. PU wound dressings with antimicrobial and therapeutic properties are emerging as valuable options to prevent wound infection and improve the healing process. This study is aimed at developing a hydrophilic antimicrobial PU foam incorporated with N. sativa oil (NSO) for potential use as a wound dressing material.

In the formulation of PU foam, polyethylene glycol (PEG) and glycerine ethoxylate were utilized to improve the hydrophilicity. PU foams were subjected to detailed analysis using electron microscopy, FTIR, mechanical properties, liquid absorption, porosity measurement, cytocompatibility, in vitro antibacterial assay, and animal evaluation.

FTIR confirmed the linkages of polyols and isocyanate in PU as well as the presence of NSO in the foam structure. The prepared foams had high porosity with homogeneous and interconnected pores. The addition of NSO to hydrophilic PU foam caused increases in tensile strength, elongation at break, and water absorption. The results of the storage experiment showed that NSO-PU foam remained stable under high humidity and temperature conditions. NSO-PU exhibited no significant toxicity on human dermal fibroblasts in the MTT assay. The presence of NSO also gave the foam antibacterial activity against Escherichia coli and Staphylococcus aureus. Histological study showed enhanced wound healing capability of NSO-PU. In NSO-PU, a thin epidermis composed of keratinocytes was observed at the wound site and the collagen deposited around the wounds treated with NSO-PU was organized and close to normal skin tissue.

These results indicate that this material can be used as a hydrophilic antibacterial wound dressing.