Selective laser sintering of aliphatic-polycarbonate/hydroxyapatite composite scaffolds for medical applications

This study investigated the selective laser sintering (SLS) of aliphatic-polycarbonate/hydroxyapatite (a-PC/HA) composite scaffolds for medical applications. The effects of material ratios and SLS processing parameters on the porosity, microstructures and mechanical properties of the samples were observed. The optimized proportion in the a-PC/HA composite was found to be 10 wt% HA. The processing parameters were optimized as: 10 W of laser power, 2000 mm/s of scan speed, 0.15 mm of scan spacing, and 0.17 mm of layer thickness. With the optimized process, the scaffold porosity and compressive module were increased to 77.36 % and 26 MPa, respectively. The pores were interconnected, indicating the existence of more space for cell ingrowth and the improvement in the load capability of bone scaffold. The nanoscale HA particles were fully or partially embedded in a-PC matrix and did not decompose during the SLS processing. Crystalline behavior, bioactive activity, and osteoconduction, beneficial for bone ingrowth, scarcely changed before and after sintering. The successful manufacturing of complex scaffold with smooth surface demonstrated that surface roughness could be controlled by optimizing HA content and adjusting the processing parameters. The a-PC/HA composite powder could be used to manufacture complex porous parts by using the SLS process for medical applications.