Platinum Nanoparticles‐Enhanced Ferritin–Mn2+ Interaction for Magnetic Resonance Contrast Enhancement and Efficient Tumor Photothermal Therapy

Nanoplatforms with high Mn²⁺ coordination can display efficient T₁ magnetic resonance imaging (MRI) contrast enhancement. Herein, an earth gravity-like method for enhanced interaction between Ferritin (Fn) and Mn²⁺ by the growth of platinum nanoparticles (PNs) in Fn's cage structure via a biomineralization method is first proposed. Fn has good biocompatibility and can provide a suitable growth site for PNs. PNs with negative charge have certain attraction to Mn²⁺ with positive charge, improving Fn's loading capacity of Mn²⁺ by attraction force; and thus, achieving efficient MRI contrast enhancement. In addition, PNs can be applied for efficient photothermal therapy (PTT) under near infrared ray (NIR) irradiation. Systemic delivery of this nanoplatform shows obvious MRI contrast enhancement and tumor progression inhibition after NIR irradiation, as well as no obvious side effects. Therefore, this nanoplatform has the potential to contribute to nanotheranostic for clinical transformation.