Silk fibroin solution is a fibrous protein. It consists of a light (L) chain polypeptide and a heavy (H) chain polypeptide linked together via a single disulfide bond at the C-terminus of H-chain, forming a H-L complex. Silk fibroin solution consists of 26 kDa light and 390 kDa heavy chain joined by a disulfide bridge. Silk fibroin’s crystalline regions are primarily composed of glycine-X repeats, where X is alanine, serine, threonine or valine. Within these domains lie subdomains that are rich in glycine, alanine, serine and tyrosine. Crystalline regions make the fibroin films insoluble in aqueous environment and therefore suitable for in vivo implantation. The result is a hydrophobic protein that selfassembles to form strong and resilient materials. The dominance of the β-sheet forming regimes within the fibroin structure imparts the protein-based materials with high mechanical strength and toughness.

Silk Fibroin is a natural polymeric biomaterial used for tissue engineering. It also can be reconstituted in various ways after a series of chemical and physical treatments. Silk fibroin solution has been highlighted as a functional biomaterial with excellent biocompatibility, low inflammation-inducing effect, excellent water vapor with oxygen permeability, blood compatibility, and controllable degradation. For these reasons, it is a popular biomaterial used in the fields of biomedicine and biotechnology.

Silk fibroin has been used in textiles and surgery for centuries. With the newly developed biomedical applications, its usage area is expanding. The facile and versatile processability of Silk Fibroin solution in native and regenerated forms makes it appealing in a range of applications that require a mechanically superior, biocompatible, biodegradable, and functionalizable material. The silk fibroin fibers are endowed with a combination of attractive strength, toughness, biocompatibility/biodegradability and thermal stability, representing one of the most impressive natural protein fibers, with properties that surpass those of many synthetic and natural fibers.