Design of 3D printed scaffolds for bone tissue engineering: A review

Every year, millions of people around the world undergo bone graft and artificial prosthesis transplants which engenders the repair and/or replacement of native bone for treating bone defects and injury. As a result, bone has become the second most transplanted tissue globally and there is a growing need for advances in bone tissue engineering (BTE) to ensure improved quality of life. The advent of 3D bone scaffolds has led to a paradigm shift in this field. These scaffolds act as an extra cellular matrix (ECM) providing a 3D environment for cell adhesion, proliferation, and differentiation. The scaffolds so fabricated, must meet the mechanical and biological criteria for successful clinical translation. Initial iterations of these scaffolds were not constructed with precise geometries. This review looks at the various advances in scaffold designs, materials and 3D printing techniques employed, which enable us to fabricate scaffolds with tailored architecture and control its functionality. These advances allow us to optimize the parameters in the fabrication of these scaffolds, such that we can create structures with desired characteristics like controllable biodegradability using the least amount of material possible along with a precise pore size and high permeability for purposes of osteo-induction and osseointegration. This is followed by the computational analysis carried out on the samples to ensure they are suitable for a given application. Finally, this paper talks about regulatory hurdles (ethical, legal and social) faced by researchers, in addition to the various technical challenges, when it comes to the real-life implementation of this technology.