Additively Manufactured Shape Memory Polycaprolactone/Thermoplastic Polyurethane Scaffolds for Bone Tissue Engineering

ABSTRACT Additive manufacturing makes it possible to produce patient‐tailored scaffolds with precisely regulated porosity for bone tissue engineering; nevertheless, stiff polymeric constructs often fail to adapt to complex, irregular defect shapes. In this work, shape memory porous polycaprolactone/thermoplastic polyurethane (PCL/TPU) scaffolds were fabricated via extrusion‐based 3D printing and systematically assessed in terms of physicochemical characteristics, compressive mechanics, and in vitro biological performance. Printing was carried out using molten polymer inks at 80°C in three compositions: 100% TPU (Sample a), 100% PCL (Sample b), and an equal 50/50 TPU/PCL blend (Sample c). FTIR analysis verified the signature functional groups of both polymers, and the lack of additional bands in the blend supported a physical combination rather than a chemical interaction. Morphological evaluation by SEM revealed uniform, well‐formed filaments and fully interconnected square pores. The mean pore size was approximately 497–502 μm, while average filament diameters were about 537 μm for TPU, 563 μm for PCL, and 630 μm for TPU/PCL. Compressive testing showed that neat PCL delivered the greatest strength (yield: 2.68 MPa; ultimate: 9.52 MPa), whereas TPU exhibited markedly higher compliance (yield: 0.051 MPa; ultimate: 0.43 MPa); the 50/50 blend produced intermediate mechanical behavior (yield: 0.75 MPa; ultimate: 1.58 MPa). Biocompatibility with SaOS2 cells was demonstrated through MTT assays (viability > 80% on Day 3 with further improvement by Day 7), DAPI and crystal violet staining, and SEM‐based adhesion observations, with the blended scaffold showing the highest cell density and pronounced spreading. Moreover, osteogenic responses increased with culture time, and the TPU/PCL scaffold yielded the most intense Alizarin Red staining and the highest ALP activity at Days 7 and 14. Overall, these findings suggest that 3D‐printed TPU/PCL scaffolds offer suitable pore architecture, an optimized compressive profile, and improved osteogenic potential, highlighting their suitability as conformable, minimally invasive matrices for bone defect repair.