Biointegration of three-dimensional-printed biomaterials and biomedical devices

Three-dimensional printing (3DP), or additive manufacturing (AM) or solid freeform fabrication, is a computer-aided manufacturing process where net-shape and complex 3D parts are made by adding materials layer-by-layer (Bandyopadhyay et al., 2011). In this process, commercial 3D computer-aided design (CAD) software is used to design the part to be fabricated, and the 3D CAD model is later sliced into horizontal cross-sections electronically. Depending on the type of 3DP process, each cross-section is built one over the other in 3DP machine. Once all layers are completed, the net-shape functional 3D components are ready for further processing or use. Processing of biomaterials is as important as choosing biomaterials for various biomedical applications. For example, the natural bone is a complex composite consisting of different materials and architecture with functional gradient in composition, macro, and microstructures. The natural gradation of the bone results in large variation in the elastic modulus (20 GPa for cortical bone outside and 0.5 GPa for central cancellous bone, which is highly porous). However, none of the existing bone replacement materials/implants have such characteristics. Therefore, to manufacture artificial implants or tissues-mimicking natural structure and properties, it is important to use state-of-the-art processing technologies such as 3DP.