Inner strut morphology is the key parameter in producing highly porous and mechanically stable poly(ε-caprolactone) scaffolds via selective laser sintering

• Published in: Materials Science & Engineering C 2021-04, Vol.123, p.111986-111986, Article 111986
• Main Authors: Tortorici, Martina, Gayer, Christoph, Torchio, Alessandro, Cho, Simone, Schleifenbaum, Johannes Henrich, Petersen, Ansgar
• Format: Article
• Language: English
• Subjects: Biocompatibility; Biodegradability; Biodegradation; Bone; Cross-sections; Cytocompatibility; Cytotoxicity; Diameters; Humans; Laser beams; Laser sintering; Lasers; Materials science; Mechanical properties; Mesenchyme; Optimization; Poly(ε-caprolactone); Polycaprolactone; Polyesters; Polymers; Porosity; Process parameters; Rapid prototyping; Scaffold; Scaffolds; Selective laser sintering; Sintering (powder metallurgy); Stability; Stiffness; Stromal cells; Struts; Tissue Engineering; Tissue Scaffolds; Toxicity
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2021.111986

Selective laser sintering (SLS) is an established method to produce dimensionally accurate scaffolds for tissue engineering (TE) applications, especially in bone. In this context, the FDA-approved, biodegradable polymer poly(ε-caprolactone) (PCL) has been suggested as a suitable scaffold material. However, PCL scaffold mechanical stability – an attribute of particular importance in the field of bone TE – was not considered as a primary target for SLS process parameters optimization so far. Here, we investigated the influence of SLS process parameters on the sintered scaffolds with the aim of producing highly porous (>70% porosity) PCL scaffolds with sub-mm geometrical features for bone TE. Specifically, we studied the influence of laser power, beam compensation and laser beam diameter on the dimensional accuracy and mechanical stiffness of the produced PCL scaffolds. We found that the ratio between the diameter of the molten cross-section within scaffold struts and the outer strut diameter (including partially sintered particles) depended on the SLS process parameters. By maximizing this ratio, the mechanical stability could be optimized. The comparison with in silico predictions of scaffold mechanical stiffness revealed that the diameter of the molten cross-section within struts and not the strut diameter controlled the mechanical behaviour of the scaffold. These observations should be considered when evaluating the quality of the sintering process based on dimensional accuracy, especially for features