Silk sericin and its biomedical applications: extraction methods, genetic insights (Ser1-Ser6), and developments of multifunctional biomaterials for tissue regeneration.

Sericin protein is derived from silk cocoons from silkworms. Sericin functions as a glue to bond the two fibroin filaments together in the silk cocoon. It is a hydrophilic, hot water-soluble macromolecular glycoprotein. In the silk industry, sericin is usually removed and discarded as waste during the degumming process of silk yarn or fabrics, often by boiling with soap water. Besides being readily available and inexpensive, sericin is biocompatible and biodegradable. In recent times, sericin has received considerable attention due to its numerous versatile properties and potential applications in various areas, including cosmetics, pharmaceuticals, food, sustained drug delivery, and the fabrication of functional biomaterials, particularly in the biomedical field. Sericin, as a biomaterial with biocompatibility, immune-compatibility, biodegradability, anti-inflammatory, antibacterial, antioxidant, and photoprotective properties, has been identified as a potential biomaterial. This review aims to outline and contextualize recent advancements in sericin research, with a special focus on tissue engineering applications. These include insight into sericin gene expression in the silkworm (Ser1 to Ser6) and the use of sericin as a biomaterial in various forms, such as films, fibers, sponges, gels, and bio-coatings for implants, as well as micro/nano vehicles for targeted delivery systems. Although sericin is mainly described as a waste-derived biomaterial, this review attempts to integrate sericin gene diversity, extraction strategies, and structure-function relationships to identify the key determinants of its translational potential for tissue engineering applications.