Multifunctional 4D printed shape memory composite scaffolds with photothermal and magnetothermal effects for multimodal tumor therapy and bone repair

Tumor recurrence and bone defects are two key challenges in the surgical treatment of osteosarcoma (OS). Therefore, it is highly necessary to develop a multifunctional scaffold that can simultaneously eradicate tumor cells and promote bone regeneration. Herein, a hierarchically porous shape memory scaffold consisting of hydroxyapatite, silica, poly(D,L-lactide-co-trimethylene carbonate) and Fe₃O₄(HSP-Fe₃O₄) is constructed by Pickering emulsion and 4D printing technique. The HSP-Fe₃O₄scaffold demonstrates the advantages of multimodal anti-tumor therapy, including chemotherapy through the Fenton reaction, effective photothermal conversion for photothermal therapy under near-infrared laser irradiation, and magnetothermal therapy provided by an alternating magnetic field. Furthermore, photothermal hyperthermia also serve as triggers for the shape memory effect of the HSP-Fe₃O₄scaffold, enabling the scaffold to precise adaptation of complex bone defects after minimally invasive surgical implantation. Additionally, the HSP-Fe₃O₄scaffold with interconnected multiscale pore exhibits good biocompatibility and excellent bone repair capabilities. This study proved that the HSP-Fe₃O₄scaffold provides positive insights for preventing tumor recurrence and facilitating bone regeneration after OS surgery.