Design of a biomimetic graded TPMS scaffold with quantitatively adjustable pore size

Abstract

The advantages of “printing the right material in the right position” and “printing the unique structure for unique function” in additive manufacturing make the design of biomimetic graded scaffold of bone tissue engineering possible. Here, under different porosities, we propose a biomimetic graded TPMS scaffold design with adjustable graded pore size, providing guidance for designing porous bone implants without the characteristics of stress concentration, stress shielding and barrier mass transport. Specifically, the structural characteristics of TPMS can be achieved without stress concentration. By adjusting the porosity, the elastic modulus of Ti6Al4V samples can be adjusted in the range of 1158–4567 MPa, which can match the individual selection of mechanical properties of the biological bone. Since the TPMS scaffold is designed by layer-by-layer splicing, through adjusting the height parameters of the single-layer structure, the selective pore size variation can be realized to further match mass transport of biological bone. Then, the in vitro culture experiments have been conducted and the maximum cell survival rate of the scaffold with an offset constant 0.4 is 85.44%, which can meet the mass transport of bone implants. As such, the proposed graded scaffold design in this paper shows excellent potential for orthopedic implants.

Keywords

• Porous material
• Graded scaffold
• Lattice structure
• TPMS
• Additive manufacturing