4D printed Stimuli Responsive Scaffold with Tissue Expansion and Photothermal Tumor Ablation Property for Post‐Mastectomy Breast Reconstruction

Breast tissue engineering is a promising alternative to post-mastectomy breast reconstruction. However, the high relapse rate (about 20%) of this malignant tumor negatively affects its long-term prognosis. Moreover, the shortage of recipient site volume often hampers the reconstruction of large-sized breast. Here, this work reports on the additive manufacturing of a novel breast tissue engineering scaffold with photothermal shape memory and tumor ablation properties to solve the aforementioned issues. Graphene nanosheets (GN) are used to functionalize the surface of 3D-printed polyurethane scaffolds (GfPU) without compromising the biocompatibility of polyurethane. Subsequently, the GfPU scaffolds are remodeled into temporary shapes using established procedures. After exposure to an 808 nm laser, the GfPU scaffolds are heated to 47.1 °C, and they converted from a temporary shape to their original shape in a light intensity-dependent manner. With an accurate structural design, the shape memory scaffold could act as a stimuli-responsive tissue expander in vivo. Meanwhile, the laser-irradiated GfPU could specifically ablate multiple breast cancer cell lines in vitro and suppress both tumor growth and tumor recurrence in vivo. This dual-functional scaffold has the potential to be used in breast tissue engineering applications to optimize both the oncological and reconstructive effect.