Osteochondral tissue engineering involves the combination of cartilage and subchondral bone, which have significant differences in biological composition, structure, and mechanical properties. Furthermore, cartilage tissue shows limited self-regeneration ability because the tissue is avascular and not innervated. Composite scaffolds made of natural or synthetic polymers and ceramics are being considered for restoration of the biological and mechanical functionality of the bone-cartilage interface. Major requirements for such materials are biodegradability, sufficient mechanical strength, and promote osseointegration and formation of ligamentous tissue. Silks as naturally occurring degradable fibrous proteins present excellent biocompatibility, unique mechanical properties, and processability. It has been identified as a suitable scaffolding material for ligament regeneration. Silk fibroin (SF) from Bombyx mori possesses biocompatibility with low inflammatory and immunogenic responses. Silk biocompatibility is enhanced via sericin stripping. The unique β-sheet structure imparts high stiffness and toughness to silk biomaterials, making it a useful biopolymer for tissue engineering applications. Among ceramic materials, β-TCP is greatly biocompatible and resorbable in tissue engineering. β-TCP implants are as osteoconductive as hydroxyapatite ceramic implants, but simultaneously they are replaced by new bone tissue after some time. Therefore, β-TCP combines the property of biodegradability with that of osteoconductivity, in such a sense that the process taking care of its biodegradation is exactly the process that also induces the formation of new bone. Incorporation of ions in β-TCP, such as strontium (Sr) and zinc (Zn) has been the subject of great interest owing to the critical role of these ions in the biological processes after implantation. Sr has beneficial effects in the treatment of osteoporosis due to the prevention of bone loss by mechanism of depressing bone resorption and maintaining bone formation; Zn is an essential trace element for promoting osteoblastic cell proliferation and differentiation and thought to possess a potent and selective inhibitory effect on osteoclastic bone resorption, in vivo.
In the present work, nanocomposites scaffolds with SF and β-TCP doped with Sr and/or Zn were prepared and characterized. The scaffolds were produced by means of solvent-casting salt-leaching.