A ferromagnetic compound with anti-cancer proeprties for controlled drug delivery and imaging

New anticancer agents and modalities for their use are of great interest. Recent studies have demonstrated the presence of anti-cancer properties in salen derivatives. We found that an iron salen derivative, i.e., [Fe(salen)]2O, displays ferromagnetic order above room temperature and shows spontaneous field-dependent magnetization and hysteresis. Understanding of this magnetic property is provided by first-principles calculations based on structures obtained by X-ray crystallography. [Fe(salen)]2O exhibited potent anti-cancer properties against various cancer cell types and was readily attracted by even moderate-strength permanent magnets in vitro. We demonstrated that the delivery of [Fe(salen)]2O to melanoma tissues transplanted into the tails of mice using a permanent magnet leads to a robust decrease in tumor size. The local accumulation of [Fe(salen)]2O was visualized by MRI. Thus, [Fe(salen)]2O acted as an anti-cancer and MRI contrast compound that has a pharmacological effect that is delivered in a controlled manner, suggesting new strategies for anti-cancer drug development.