Osteogenesis of adipose-derived stem cells on polycaprolactone-β-tricalcium phosphate scaffold fabricated via selective laser sintering and surface coating with collagen type I.

The current study aimed to fabricate three-dimensional (3D) polycaprolactone (PCL), polycaprolactone and β-tricalcium phosphate (PCL-TCP) scaffolds via a selective laser-sintering technique (SLS). Collagen type I was further coated onto PCL-TCP scaffolds to form PCL-TCP-COL scaffolds. The physical characters of these three scaffolds were analysed. The osteogenic potential of porcine adipose-derived stem cells (pASCs) was compared among these three scaffolds in order to find an optimal scaffold for bone tissue engineering. The experimental results showed no significant differences in pore size and porosity among the three scaffolds; the porosity was ca. 75-77% and the pore size was ca. 300-500 µm in all three. The compressive modulus was increased from 6.77 ± 0.19 to 13.66 ± 0.19 MPa by adding 30% β-TCP into a 70% PCL scaffold. No significant increase of mechanical strength was found by surface-coating with collagen type I. Hydrophilicity and swelling ratios showed statistical elevation (p < 0.05) after collagen type I was coated onto the PCL-TCP scaffolds. The in vitro study demonstrated that pASCs had the best osteogenic differentiation on PCL-TCP-COL group scaffolds, due to the highest ALP activity, osteocalcin mRNA expression and mineralization. A nude mice experiment showed better woven bone and vascular tissue formation in the PCL-TCP-COL group than in the PCL group. In conclusion, the study demonstrated the ability to fabricate 3D, porous PCL-TCP composite scaffolds (PCL:TCP = 70:30 by weight) via an in-house-built SLS technique. In addition, the osteogenic ability of pASCs was found to be enhanced by coating COL onto the PCL-TCP scaffolds, both in vitro and in vivo.