Chapter 32 - Natural Origin Materials for Bone Tissue Engineering – Properties, Processing and Performance

This chapter focuses on properties, processing, and performance of natural origin materials employed for bone tissue engineering. One of the materials is starch, a predominant energy-storing compound in many plants. Due to the thermoplastic behavior of the starch-based blends and composites, it is possible to produce 3D porous scaffolds using traditional melt-based technologies, such as compression molding combined with particulate leaching, and injection molding or extrusion with blowing agents. The two types of scaffolds produced by this method exhibit a typical fiber-mesh structure, with a fiber diameter of approximately 180 μm for SPCL and 210 μm for SPLA, with highly interconnected pores and a porosity of approximately 75%. Another material is chitosan, a homopolymer of β (1→4)-linked N-acetyl-D-glucosamine residues. A very interesting property of chitosan is that it can be transformed into 3D highly porous structures with a high degree of interconnectivity using various technologies; for example, porous scaffolds can be produced by lyophilizing a frozen solution of chitosan powder dissolved in acetic acid. The obtained scaffolds have porosities of ∼ 80% and median pore diameters of ∼ 68 μm. The mean pore diameters can be controlled within the range of 1-250 μm by varying the freezing conditions. Wet spinning is one of the most used methods to produce natural fibers and has been used to prepare chitosan fibers and 3D fiber meshes. The obtained scaffolds have an average pore size in the range of 100-500 μm, which is ideal for bone-related applications.