A novel comby scaffold with improved mechanical strength for bone tissue engineering

Porous scaffold is an integral part of bone tissue engineering. However, low mechanical strength is a major challenge. A biomimetic comby scaffold was designed to get an improvement of strength in this paper. Fabrication of this bone scaffold involved first creating a pore-forming mold by using three-dimensional printing (3DP), which was cast into chitosan/nano-hydroxyapatite (CS/nHA) powders to create an inverse mold. The sacrificial mold and inverse one were then pressed by cold isostatic pressing as a whole in order to enhance the strength. Finally, the wax template was removed, resulting in a scaffold with honeycomb geometry. Compression tests were carried out to evaluate the strength of the scaffold. The behaviors and responses of preosteoblast cells on the scaffold were studied as well. The scaffold with high porosity were found to display improved compressive strength (1.62 ± 0.22 MPa) and Young's modulus (110 ± 22 Mpa) approaching the values of cancellous bone. Moreover, MC3T3-E1 cells exhibited good proliferation on the scaffold. The comby scaffold had great application potential in bone tissue engineering. This novel structural bionic approach would offer some new ideas in design and fabrication of porous scaffolds for tissue engineering.