Process flow for designing functionally graded tissue engineering scaffolds

The combination of Computer Aided Design (CAD) and Rapid Prototyping (RP) system have been aiding tissue engineers in designing customized tissue scaffolds to meet the biological, mechanical and anatomical requirements. Biological requirements include suitable biomaterial and pore size for cell growth, while anatomical requirement can be fulfilled by shaping the scaffold to fit the defect site. Mechanically, scaffolds should have matching mechanical properties, such as compressive stiffness and strength, with the target organ, especially in bone regeneration, as bone is a load-bearing organ. Bone possesses stiffness gradient, depending on its function and the amount of load it needs to bear. Hence scaffolds for bone regeneration should possess stiffness gradient mimicking bone by varying the scaffold porosity and structure. This article presents the sequences on designing bone scaffolds with stiffness gradient using CASTS, which stands for Computer Aided System for Tissue Scaffolds, as a platform. As a case study, the regeneration of human mandibular cancellous bone with stiffness gradient will be presented. These sequences are to be further implemented into the current CASTS system to automate the design of Functionally Graded Scaffolds (FGS).