Fibroin: an example of hierarchy and conformation dominate biological behavior

Silk-fibroin proteins have recently attracted wide attention as bioactive matrices for biomedical applications. In vitro and in vivo studies have demonstrated the ability of fibroin to favourably interact with cells and the advantageous use of fibroin scaffolds to engineer the repair and regeneration of different types of tissues. Cell seeded or unseeded scaffolds have been successfully tested for soft and hard tissues repair, in the form of gels, sponges, fibres or films, adapted to a variety of repair sites and clinical needs. As for other natural polymers, silk possesses a complex hierarchical structure that is assembled from the bottom-up, where each pattern/conformation can be correlated to specific biological functions or physical properties. Self-assembly and the resulting conformation of silk fibroin depends however on silk source and processing conditions, that in turn affect the biological and physical behaviour of the material. This fact adds complexity to the understanding and control of the materials/biological system crosstalk and should be carefully assessed when biologically engineering reproducible scaffold. The presentation will be focused on the interactions between silk fibroin and cells. Specific hints on the effect of processing on silk conformation and function-structure relationships will be discussed in light of fabricating responsive devices applicable in regenerative medicine