The effect of hydroxyapatite nanoparticles on mechanical behavior and biological performance of porous shape memory polyurethane scaffolds.

The scaffold which provides space for cell growth, proliferation, and differentiation, is a key factor in bone tissue engineering. However, improvements in scaffold design are needed to precisely match the irregular boundaries of bone defects as well as facilitate clinical application. In this study, controllable three-dimensional (3D) porous shape memory polyurethane/nano-hydroxyapatite (SMPU/nHAP) composite scaffold was successfully fabricated for bone defect reparation. Detailed studies were performed to evaluate its structure, apparent density, porosity, and mechanical properties, emphasizing the contribution of nHAP particles on shape recovery behaviors and biological performance in vitro. The effect of nHAP particles in porous SMPU/nHAP composite scaffold was found to enhance the compression resistance by 37%, shorten the compression recovery time by 41%, reduce the tensile resistance by 78%, reach the shape recovery ratio of 99%, and promote the cell proliferation by 13% after 7 days of culture. These results revealed that the 3D structure and aperture of as-prepared scaffold were controllable. And in minimally invasive surgery and bone repair surgery, this porous composite scaffold could significantly reduce the operative time and promote the bone cell growth. Therefore, this porous SMPU/nHAP composite scaffold design has potential applications for the bone tissue engineering.