Doping lithium element to enhance compressive strength of β-TCP scaffolds manufactured by 3D printing for bone tissue engineering

Abstract The purpose of this study was to enhance the compressive strength of 3D printed beta-tricalcium phosphate (β-TCP) scaffolds for bone tissue engineering. Ca10Li(PO4)7 (CLP) is acquired by doping Li into β-TCP. The optimum sintering temperature of CLP was determined by compressive strength, relative density, microstructure, grain size and the behaviors of cracks. The dense structure and porous scaffolds of CLP were manufactured by 3D printing. Cell viability and cell morphology of mouse osteoblast cell line (MC3T3-E1) were evaluated by the cell counter kit-8 assay (CCK-8) and fluorescence microscope, respectively. The mineralization effects and degradation property in vitro of CLP scaffolds were investigated as well. The optimal sintering temperature of CLP is 1000 °C. The pores size of scaffold is about 400 × 400 μm and 400 × 300 μm in the Z-axis and XY-axis direction, correspondingly. The compressive strength of the dense structure (332.24 ± 17.81 MPa) and porous scaffold (69.12 ± 20.62 MPa) of CLP is approximately three times as large as that of β-TCP (100.89 ± 9.33 MPa, 24.14 ± 5.01 MPa). There is no statistical difference in cytotoxicity between CLP and β-TCP at the diverse culture days (p > 0.05). The scaffolds of CLP have the closer mineralization effects and degradation property in vitro to β-TCP. Possessing higher strength and excellent biocompatibility, CLP scaffolds manufactured by 3D printing have significant clinical potentials in bone tissue engineering.