Injectable ferrimagnetic silk fibroin hydrogel for magnetic hyperthermia ablation of deep tumor.

Due to the well-recognized biocompatibility, silk fibroin hydrogels have been developed for biomedical applications including bone regeneration, drug delivery and cancer therapy. For the treatment of cancer, silk-based photothermal agents exhibit the high photothermal conversion efficiency, but the limited light penetration depth of photothermal therapy restricts the treatment of some tumors in deep positions, such as liver tumor and glioma. To provide an alternative strategy, here we developed an injectable magnetic hydrogel based on silk fibroin and iron oxide nanocubes (IONCs). The as-prepared ferrimagnetic silk fibroin hydrogel could be easily injected through a syringe into tumor, especially rabbit hepatocellular carcinoma in deeper positions using ultrasound-guided interventional treatment. Compared with photothermal agents, the embedded IONCs endowed the ferrimagnetic silk fibroin hydrogel with remote hyperthermia performance under an alternating magnetic field, resulting in the effective magnetic hyperthermia of deep tumors including subcutaneously implanted tumor model in Balb/c mouse after the coverage of a fresh pork tissue and orthotopic transplantation liver tumor in rabbit. Furthermore, due to the confinement of IONCs in silk fibroin hydrogel, the undesired thermal damage toward normal tissue could be avoided compared with directly administrating monodispersed magnetic nanoparticles.