Immobilization of Arg‐Gly‐Asp peptides on silk fibroin via Gly‐Ala‐Gly‐Ala‐Gly‐Ser sequences

A simple method by which the functional peptide of Gly‐Arg‐Gly‐Asp‐Ser (GRGDS) is immobilized on the surface of silk fibroin (SF) films via Gly‐Ala‐Gly‐Ala‐Gly‐Ser (GAGAGS) sequences is proposed. GAGAGS, a repeating amino acid sequence in the crystal region of Bombyx mori SF, performs a key role in interacting with and immobilizing SF molecules. Immobilization by this proposed method involves no chemical reaction, thereby preserving the original properties of the SF molecule. The density of GRGDS peptides existing on SF film was found to be higher in the GAGAGS‐bound type than in the non‐GAGAGS‐bound type. Furthermore, results showed that the amount of immobilized (GAGAGS)GRGDS peptide increased as the β‐sheet crystallization was promoted in the SF film. Fibroblasts, which adhered to the surface of the SF film, showed more extensibility because of the (GAGAGS)GRGDS immobilization, which suggests that the cell adhesion activity of RGD is functioning effectively. Graphical and Lay Summary Many studies on Arg‐Gly‐Asp (RGD)‐peptide‐immobilized polymeric biomaterials have been conducted. Silk fibroin (SF) films were modified using Gly‐Arg‐Gly‐Asp‐Ser (GRGDS) peptides with Gly‐Ala‐Gly‐Ala‐Gly‐Ser (GAGAGS) sequences. The results suggest that GRGDS peptides were immobilized via the GAGAGS sequence on SF materials and that they play a role in the cell behavior on SF films. This immobilization approach has considerable potential for adoption in the development of functional SF‐based biomaterials for tissue regeneration/repairs.