The influence of elastomeric polyurethane type and ratio on the physicochemical properties of electrospun polyurethane/silk fibroin hybrid nanofibers as potential scaffolds for soft and hard tissue engineering

Hybrid materials and structures have been known as multifunctional polymers used for various commercial productions. Recently, biomaterials have become an emerging research field for tissue engineering applications. In this study, the hybrid fibrous scaffolds of two various types of aliphatic elastomeric polyurethane (EPU) and silk fibroin (SF) were fabricated with different mass ratio by electrospinning. Physical and mechanical properties of these scaffolds were evaluated using scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, contact angle measurement, atomic force microscopy and tensile strength analysis. Viability and attachment of human foreskin fibroblasts on the scaffolds were also assessed by MTT assay, hematoxylin-eosin and fluorescent staining and SEM. The results showed that in both types of polyurethane, by increasing the percentage of fibroin to polyurethane, the fibers diameter decreased and the uniformity of their diameter increased. Unexpected ultrafine fibers and nanowebs were seen throughout the usual fibers of EPU/SF hybrid scaffolds. Thus, the efficiency of the homing and proliferation of the fibroblasts cells onto the scaffolds was improved. Based on our results, the EPU/SF hybrid scaffolds characteristics, especially morphology, mechanical properties and biocompatibility were tunable by altering the ratio and the type of EPU. These features make these adjustable hybrids as suitable scaffolds for reconstitution of a wide range of organs such as skin, liver, uterus, esophagus, vasculature, tracheal cartilage, neurons and others.