Selective laser sintering of β-TCP/nano-58S composite scaffolds with improved mechanical properties

Highlights: • The porous β-TCP/nano-58S composite scaffold was successfully fabricated by selective laser sintering. • Nano-58S transformed from the dispersed phase to the continuous phase with the increasing of the concentration. • Nano-58S as the dispersed phase reinforced the mechanical properties of the composite scaffold. • The incorporation of nano-58S improved the bioactivity of the scaffold due to its unique biological properties and nano-size. - Abstract: Nano-sized 58S bioactive glass (nano-58S) as the dispersed phase was added to β-tricalcium phosphate (β-TCP) to reinforce the mechanical properties, and then the β-TCP/nano-58S composite scaffolds were prepared via selective laser sintering (SLS). The effects of nano-58S on microstructure, mechanical properties, bioactivity, and biocompatibility of the composite scaffolds were evaluated. The results showed that nano-58S was homogeneously dispersed in the β-TCP matrix and the mechanical properties were gradually improved when the amount of nano-58S was no more than a certain value (15 wt.%). However, exceeding this value, nano-58S became the continuous phase and exhibited the brittleness of bioactive glass. Accordingly, the mechanical properties gradually decreased. The maximum fracture toughness and compressive strength were 1.347 ± 0.025 MPa · m^1/2 and 18.2 ± 0.62 MPa, respectively. In vitro tests in the simulated body fluid (SBF) demonstrated that the apatite-like layer formed faster on the composite scaffolds than on the scaffold without nano-58S, indicating that the nano-58S glass could enhance the bioactivity of the composite scaffolds. The MG-63 cells culture experiment proved that nano-58S glass could further facilitate the growth of human osteoblastic cells.