One of the main goals of bone tissue engineering is the development of scaffolds that mimic both functional and structural properties of native bone itself. This study describes the preliminary work carried out to assess the viability of using three dimensional printing (3DP) technology for the fabrication of porous titanium scaffolds with lowered modulus and improved biocompatibility. 3DP enables the manufacturing of three dimensional (3D) objects with a defined structure directly from a Computer Aided Design (CAD). The overall porosity of the 3D structures is contributed by the presence of both pores-by-process (PBP) and pores-by-design (PBD). This study mainly focuses on the PBP, which are formed during the sintering step as the result of the removal of the binding agent polyvinyl alcohol (PVA). Sintering temperatures of 1250oC, 1350oC and 1370oC were used during the fabrication process. Our results showed that by varying the binder percentage and the sintering temperature, pores with diameters in the range of approximately 17-24 μm could be reproducibly achieved. Other physical properties such as surface roughness, porosity and average pore size were also measured for all sample groups. Results from subsequent cell culture studies using adipose tissue-derived mesenchymal stem cells (ASCs) showed improved attachment, viability and proliferation for the 3DP titanium samples as compared to the two-dimensional (2D) dense titanium samples. Hence, based on our current preliminary studies, 3DP technology can potentially be used to fabricate customized, patient-specific metallic bone implants with lowered modulus. This can effectively help in prevention of stress-shielding, and enhancement of implant fixationin vivo. It is envisioned that an optimized combination of binder percentage and sintering temperature can result in the fabrication of scaffolds with the desired porosity and mechanical properties to fit the intended clinical application.
Three-Dimensional Printing for Craniofacial Bone Tissue Engineering
