Effects of stretching-shape recovering process on the cytocompatibility of novel shape memory polyurethane for bone repair / 中国组织工程研究

ABSTRACT

BACKGROUND: Shape memory polyurethane (SMPU) may be employed for bone repair capable of resisting stress shielding and bone non-union due to the shape memory effect responding to changed external temperature. Evaluating the cytocompatibility of SMPU is important for its further in vivo experiments and applications. However, few have been done to investigate the cytocompatibility of SMPU after encounted from deforming and shape recovering.OBJECTIVE: To evaluate the osteoblast compatibility of SMPU before and after stretching-shape recovering process. METHODS: Solvent casting method was used to fabricate SMPU films; the obtained SMPU films were stretched to 200%, and then fixed and finally recovered to its odginal shape at T_g+15 ℃, T_g-15 ℃ and T_g+15 ℃, respectively. Atomic force microscope (AFM) with tapping mode was employed to probe the surface morphology and phase separation of SMPU. Primary osteoblasts at 3-5 passages were seeded on SMPU films in vitro to evaluate the adhesion, proliferation and spreading of osteoblasts. RESULTS AND CONCLUSION: There were obvious and regular phase separation resulted from soft segments and hard segments in SMPU, and some groove-ddge architectures within a scale of micrometers were produced by the stretching-shape recovering process. These special micropatterned structures promoted osteoblast adhesion and proliferation, and also resulted in partially oriented cell growth along the grooves. Shape memory process, i.e. stretching-shape recovering process may obviously change the surface morphology of SMPU films, and suggesting better biocompatibility with osteoblasts.