Development and characterization of bio-based polyurethane flexible foams containing silver nanoparticles for efficient dermal healing application

Abstract

Polymers are used in various industries and, particularly in the medical industry, the use of skin-friendly, biocompatible materials is essential. In this field, using natural and biocompatible carbonaceous materials to replace petroleum-derived materials is the most efficient solution. In this study, which was performed in two phases, polyurethane foam made from natural polyol obtained from rapeseed oil (RPO) and containing silver (Ag) nanoparticles for use in wound dressings was prepared and examined. In the first phase, bio-based polyurethane was prepared via a specific method and characterized using Fourier-transform infrared and nuclear magnetic resonance analysis. Polyol foams were prepared using different ratios of natural polyol to a petroleum based polyol. The results of the water absorption test showed that PF-NPO-35 (containing 35% natural polyol) has a 145% absorption rate. The water vapor transfer rate test was also conducted on this sample, giving results in the range of 8–9 mg cm⁻² h⁻¹, which is a suitable range for a wound dressing application. After selecting PF-NPO-35 as the optimal sample, different amounts of Ag nanoparticles were added to this sample and the final foams with different percentages of Ag nanoparticles were prepared. The antibacterial properties of the samples showed that PF-NPO-35-Ag-7 (7% Ag nanoparticles) was more sensitive to Escherichia coli than to Staphylococcus aureus. Increasing the amount of Ag nanoparticles improved the antibacterial properties. Cytotoxicity tests also showed that all samples containing Ag nanoparticles survived for 48 h. High levels of cell viability were observed in the presence of the synthetic foams. In the animal tests, the healing process of the wounds treated with a sample containing silver nanoparticles showed improved progress after 14 days.