Multifunctional Shape-Memory Polyurethane/MnO2 Composites for Postsurgical Osteosarcoma Adaptive Treatment

Treatment of postsurgical osteosarcoma remains one of the major challenges in orthopedic clinics. Conventional implants often fail to address complex pathological issues, including irregular bone defects, residual tumor cells, and delayed bone regeneration. Herein, this study reports a multifunctional shape-memory polyurethane (SMPU)/manganese dioxide (MnO2) composite that provides adaptive support, antitumor activity, and osteogenic bioactivity. SMPU was synthesized by introducing 1,4-butanediol (BDO) and dimethylolpropionic acid (DMPA) as chain extenders at a specific ratio. Commercial MnO2 nanoparticles were incorporated as both a photothermal agent and a bioactive component to achieve multifunctionality. As designed, a coordination system was formed between the polymer chains and MnO2 nanoparticles within the composites. The influence of MnO2 content was systematically investigated. Although increasing MnO2 amounts improved photothermal and mechanical performance, excessive incorporation adversely affected the molecular structure and compromised the composite’s biocompatibility. By adjusting the MnO2 content, the composites were demonstrated to possess robust mechanical performance, good shape-memory behavior, and controllable Mn2+ release. Additionally, the composites exhibited tunable photothermal performance under near-infrared (NIR) irradiation. Furthermore, in vitro studies confirmed that the composites containing 4 wt% MnO2 could eliminate tumor cells via photothermal effects and promote the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs). Overall, the SMPU/MnO2 composites had superior multifunction for treating irregular bone defects following bone tumor surgery.