An innovative approach based on electrospun wool keratin scaffolds added with gold nanoparticles for bone regeneration

Recovery and valorisation of biopolymers obtained from cheap and renewable sources have an important impact on biomedical applications. Among all, keratin is a cysteine-rich protein that can be extracted from various sources, including low-cost, renewable and abundant biosources such as raw wool. Wool keratin is biocompatible, biodegradable, bioresorbable, non-immunogenic, does not induce inflammatory responses, and improves cellular adhesion. In regenerative medicine, one of the major issues is the repair and reconstruction of bone defects. This research work focuses on the development and characterization of scaffolds composed of keratin extracted from waste wool fibres added with gold nanoparticles for bone repair and regeneration. To better mimic the composition and behaviour of bone tissue, the electrospinning technique is used to obtain nanofibrous membranes with a high surface-to-volume ratio. Furthermore, the addition of gold nanoparticles gives higher antibacterial properties to the bio-based membranes. The keratin-based scaffolds are characterized in terms of mechanical properties, biocompatibility and antibacterial activity. Biocompatibility is evaluated by performing cell viability tests on human osteoblast-like SaOs-2 cells. The presence of gold nanoparticles in keratin-based scaffolds promotes cell growth on the surface of the scaffolds and also reduces the early process of bacterial adhesion (after 3h) of Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. Hence, the nanofibrous keratin-based membranes can play a crucial role in tissue engineering, representing a promising alternative to the conventional use of bone grafts for bone regeneration. Further studies will be performed to better evaluate their potential and their antibacterial properties.