Interfacial Roughness‐Reinforced Magnetic Nanosheet Colloidal Gels for Stable Embolization and Magnetothermal Therapy of Hepatic Tumor

Abstract Injectable hydrogels have been developed for transcatheter arterial embolization (TAE) of hepatic tumor owing to their flexibility in injection and embolization. However, the dual requirement for high mechanical robustness and good injectability poses a fundamental challenge, as improvements in one often compromise the other. Colloidal gels offer tunable mechanical properties and feasible injectability through the bottom‐up assembly of building blocks. Here an interfacial reinforcement strategy is developed by enhancing specific surface area and roughness to fabricate nanosheet‐mica (NM) magnetic colloidal gels (NMMG). The negatively charged NM, exfoliated from natural ground mica (GM), possessed increased binding sites, while in situ grown Fe 3 O 4 nanoparticles enhanced building block roughness, reducing intergranular displacement and thereby maintaining mechanical strength while ensuring injectability. Compared with GM‐based magnetic colloidal gels, NMMG can be injected through 2.6 F catheter with ≈20 N force (40% of manual limit), while storage modulus improved from ≈800 to ≈1800 Pa (2.25‐fold higher than embolization minimum limit). Transcatheter embolization with NMMG significantly inhibited tumor growth. Furthermore, NMMG‐mediated minimally invasive therapies, including TAE combined with magnetothermal therapy, achieved synergistic therapeutic effects in hepatic tumor‐bearing rabbits. The rough‐interface strengthening strategy facilitates the development of high‐performance colloidal gels with mechanical integrity and tailored functions.