Fabrication of porous β-TCP/58S bioglass scaffolds via top-down DLP printing with high solid loading ceramic-resin slurry

Abstract

High solid loading of ceramic slurry limits the wider use of digital light processing (DLP) in the production of porous ceramic scaffolds with advanced functions. The top-down digital light processing (DLP) system is a potential method to achieve ceramic-resin slurry with high solid loading. Porous β-tricalcium phosphate/58S bioglass (β-TCP/BG) scaffolds with high solid loading ceramic slurry were fabricated by the top-down DLP technique in this paper. Photosensitive β-TCP/BG-resin slurries with various solid loadings for DLP were developed and the effects of solid loading on viscosity and curing reactivity were evaluated. The microstructure, mechanical strength, porosity, and shrinkage of the composite scaffolds were then explored. The results show that the maximum viscosity of the β-TCP/BG-resin slurry for top-down DLP technique was 85.92 Pa s with a solid loading of 60 wt%. The cure depth and overgrowth tended to decrease with the solid loading. The curing depth exceeds 100 μm at each solid loading after 18000 ms irradiation time. The shaping error and sintering shrinkage of the porous structure were estimated, and it was found that the pore size and sintering shrinkage reaching a minimum value for the scaffolds fabricated by the slurry of 60 wt%. The compressive strength of the β-TCP/BG scaffolds increased with the solid loading increased, reaching a maximum value of 11.43 ± 0.4 MPa for the solid loading of 60 wt%. β-TCP/BG scaffolds exhibited an alkalescent pH environment and an improved ability of apatite-mineralization formation, meanwhile Ca, P and Si were gradually released from scaffolds. Furthermore, in vitro evaluation of β-TCP/BG scaffolds was carried out to assess the osteogenic capability. The composite scaffolds displayed intensifying biocompatibility and can facilitate osteoblast proliferation, adhesion, and differentiation. The β-TCP/BG composite scaffold fabricated by top-down DLP with high solid loading ceramic slurry could be considered as a promising alternative substitute even for load-bearing bone tissue engineering applications.