Studying the combined effect of layer thickness and solid loading percentage for improving the compressive strength of 3D printed β-TCP scaffold by LCD technique

Abstract

Customized 3D printed bio-ceramic scaffolds with complex shapes can be fabricated by Liquid Crystal Display (LCD) technology. In this study we investigated the combined effect of the solid loading percentage of the β-Tricalcium phosphate (β-TCP) bio-ceramic powder and the 3D printing layer thickness on the compressive strength of the 3D printed bio-ceramic scaffolds using LCD technique. Three different high solid loadings (40, 60 and 80 vol%) of β-TCP were mixed with resin in the presence of Oleic acid prior to the 3D printing. The β-TCP:resin slurry was used to fabricate scaffolds by using three different layer thicknesses (50 μm, 100 μm and 150 μm). The 3D printed green scaffolds were thermally debinded at 530 °C for 8 h and sintered at 1000 °C for 6 h based on the TGA and DSC thermal analysis of the β-TCP-resin slurry. The x-ray diffraction (XRD) and the Fourier transform infrared (FTIR) spectroscopy analysis confirmed that the β-TCP structure is preserved after scaffold fabrication. The Scanning Electron Microscopy (SEM) analysis showed the surface morphology of the scaffolds with internal pores, micro porosity, and localized delamination. The main finding of the results suggests that decreasing the layer thickness and the solid loading will enhance the compressive strength of the scaffold. Maximum compressive strength attained was (0.19 ± 0.01 MPa) for scaffolds with 40 % solid loadings, layer thickness of 50 μm and porosity 83.49 %. These results demonstrate the potential of using the low-cost LCD 3D printing in fabricating a customized porous β-TCP scaffolds for bone tissue engineering.