Effect of hydroxyapatite on biodegradable scaffolds fabricated by SLS

Selective laser sintering (SLS) has the potential to fabricate bioresorbable polymer / ceramic composite scaffolds with pre-designed external and internal architecture that can be used for bone tissue engineering applications. Scaffolds were fabricated using poly-F-caprolactone as the base material. The effect of 15 and 30 wt% of hydroxyapatite (HA) addition was investigated in terms of compressive properties, accuracy, surface topology, and wettability. Fabricated dimensions of PCL microstructures showed great deviations from their nominal values. Average surface roughness was found to be Ra = 25 +/- 4 mu m. Increased RA content had no statistically significant effect on accuracy and surface roughness. However the addition of HA had a significant influence on compressive properties, hydrophobicity and wettability of the samples. Addition of 30 wt% HA improved initial compressive modulus of pure PCL scaffolds from 1.31 +/- 0.08 MPa to 1.58 +/- 0.18 MPa. Yield strength values increased from 0.14 +/- 0.07 MPa to 0.17 +/- 0.01 MPa by adding 15 wt% of HA, but decreased with further HA addition. Yield strain for all compositions was over epsilon = 0.06. Increased HA content decreased hydrophobicity and increased wettability of scaffold surfaces. The study demonstrated the ability of SLS to fabricate tissue engineering scaffolds, and the positive effect of HA particle reinforcement in terms of compressive mechanical properties and surface characteristics.