Silk fibroin in medicine

Biologically inspired materials and design has become an important and increasingly widespread movement towards innovative approaches in different fields such as robotics, sensors, electro-optical materials and biomedical devices. Specifically in tissue engineering and regenerative medicine, nature can provide a powerful set of new design parameters and strategies such as: sophistication, miniaturization, hierarchical organization, hybridization, resistance and adaptability. Biopolymers can be inspired by these natural parameters and can be tailored to illicit specific behavior in response to environmental stimuli. Silk fibroin is a good example of a natural biopolymer for its molecular and supra-molecular structure, its bioactivity due to molecular ligands, and it’s ability to self-assemble. Fibroin can be processed by various techniques to obtain different structures with tailored mechanical and biological properties. The combination of biopolymers with favorable cellular cues is a necessary obstacle to overcome in tissue engineering. By adjusting biopolymer architecture and chemical composition, it is possible to influence the formation of the extra cellular matrix (ECM) and ultimately guide cells to generate functional tissues. Fibroin can be processed to obtain powders, films, gels, nano- and micro-nets, sponges, that are suitable for scaffolds whose properties can be tailored and designed to specific applications. The potential of applying silk-based materials to induce regeneration of various mammalian tissues such as bone, cartilage, tendon and skin, is increasingly reported. However, silk materials can differ widely in composition, structure and properties depending on the specific source as well as on their following processing. In particular, protein conformation is critical to biological functions, driving a different protein adsorption and/or cell material cross talk. For instance, as recently shown tailoring of the crystallinity degree and morphologies can be exploited to induce different blood responses in terms of platelet adhesion and activation. These chapter overviews about 20 years of research activities performed on Bombyx mori silk fibroin processing, properties and applications.