Continuous O₂‑Evolving MnFe₂O₄ Nanoparticle-Anchored Mesoporous Silica Nanoparticles for Efficient Photodynamic Therapy in Hypoxic Cancer

Therapeutic effects of photodynamic therapy (PDT) are limited by cancer hypoxia because the PDT process is dependent on O₂ concentration. Herein, we design biocompatible manganese ferrite nanoparticle-anchored mesoporous silica nanoparticles (MFMSNs) to overcome hypoxia, consequently enhancing the therapeutic efficiency of PDT. By exploiting the continuous O₂-evolving property of MnFe₂O₄ nanoparticles through the Fenton reaction, MFMSNs relieve hypoxic condition using a small amount of nanoparticles and improve therapeutic outcomes of PDT for tumors <i>in vivo</i>. In addition, MFMSNs exhibit T₂ contrast effect in magnetic resonance imaging (MRI), allowing <i>in vivo</i> tracking of MFMSNs. These findings demonstrate great potential of MFMSNs for theranostic agents in cancer therapy