Dual Photothermal and Magnetothermal Responsive Shape Memory Polyurethane with Magnetic Navigation Capability

Shape memory polymers (SMPs) with remote activation capabilities have garnered significant attention in biomedical applications. However, traditional activation methods exhibit limitations in tissue penetration depth and spatial-temporal control precision. Here, we report a multifunctional SMP system that synergistically integrates Fe₃O₄ nanoparticles and neodymium-iron-boron (NdFeB) microparticles to achieve simultaneous magnetic navigation and dual-mode thermal activation. The NdFeB microparticles, magnetized under external magnetic fields, provide superior magnetic moments for precise navigation control, while Fe₃O₄ nanoparticles enable both near-infrared II (NIR-II) photothermal conversion and magnetothermal heating under alternating magnetic fields (AMF). Additionally, the resulting magnetic polyurethane (MPU) exhibits excellent shape memory performance with rapid activation kinetics and high recovery ratios while maintaining superior mechanical properties and biocompatibility. Cell viability studies demonstrate minimal cytotoxicity, and animal experiments confirm successful magnetic navigation, precise shape recovery, and the absence of inflammatory responses in physiological environments. The findings demonstrate that this integrated MPU platform has significant potential for applications in minimally invasive surgical instruments, smart tissue scaffolds, and targeted therapeutic delivery systems.