H2O2-Responsive MB–BSA–Fe(III) Nanoparticles as Oxygen Generators for MRI-Guided Photodynamic Therapy

The local tumor hypoxia has become one of the main obstacles for photodynamic therapy (PDT).To break through this barrier, the fabrication of O 2 -evolving nanoplatform has been more significant. Herein, the uniform methylene blue (MB)–bovine serum albumin (BSA)–Fe(III) nanoparticles (MB–BSA–Fe(III) NPs) were successfully synthesized by biomineralization approach. MB–BSA–Fe(III) NPs show high loading capacity of MB, and Fe(ΙΙΙ) has excellent catalytic performance towards abundant H 2 O 2 in cancer cells to generate O 2 , overcoming tumor hypoxia. All these combination effects remarkably increase the therapeutic efficiency of PDT, resulting in almost complete destruction of cancer cells. Most importantly, MB–BSA–Fe(III) NPs exhibit T 2- magnetic resonance imaging, which have the potential for precise visualization of the tumor location. Our results demonstrate that MB–BSA–Fe(III) is a novel H 2 O 2 -responsive and O 2 -evolving nanoplatform and it has great potential for clinical applications such as cancer diagnosis, treatment or drug delivery.