Modification of Fibroin Film with A Chimera Fibroin Fragment for Improvement of Cell Adhesion

Silk fibroin is a naturally occurring structural protein with good mechanical properties used in a variety of forms, such as powder, fiber, film, and gel. Although silk fibroin is potentially suitable for use in tissue engineering, it lacks cell regulation functions such as cell adhesion, growth, metabolism, and differentiation. The immobilization of biologically active molecules such as proteins and peptides has been reported as promising in controlling cell behavior. Silk fibroin's phase transition is characterized by a conformational change of protein from a random coil to a beta sheet. During phase transition, biological molecules can be stably entrapped in silk fibroin without the use of chemicals. We designed a novel immobilization using this phase transition mechanism with a chimera fibroin fragment. The chimera fibroin fragment was constructed by linking a bioactive peptide to fibroin fragments including crystal regions. In the first study, a synthetic oligonucleotide encoding Arg-Gly-Asp peptide which promotes cell adhesion, was fused to the fibroin fragment gene through inframe gene fusion, and the chimera fibroin (RGD-fibroin) gene was expressed by E.coli. This paper discusses RGD-fibroin construction, and the results of cell adhesion on fibroin films containing RGD-fibroin.