Beyond natural silk: Bioengineered silk fibroin for bone regeneration

Bone regeneration and repair are among the most challenging clinical challenges to overcome. Despite extensive research on bone-tissue repair and regeneration, it remains difficult to achieve perfect regeneration and repair of bone tissue using the current treatments. One new treatment is bone-tissue engineering (TE), which has attracted attention because of its low invasiveness. Silk fibroin (SF), a high-molecular-weight natural fibrous protein secreted by silkworms and spiders, is an ideal choice for melt electrowriting (MEW) of bone TE scaffolds owing to its superior mechanical properties, controlled biodegradation rate, and high biocompatibility. It contains 18 essential amino acids and is widely used in bone grafting. Their physical and chemical properties may be essential for stem cell growth and differentiation, making them ideal scaffold materials for bone TE. In this review, the three primary components of bone TE and the bone-healing process are presented. With an emphasis on recent advancements and the use of bone TE, both in vitro and in vivo, we examined the use of SF in bone TE from the standpoint of its origin and structure. To offer new concepts and avenues for related research, we have also looked at the possible topics for SF research and the present difficulties.