Jonghoon Kim1 2

1, Seoul National University, Seoul, SE, Korea (the Republic of)
2, Institute for Basic Science, Seoul, , Korea (the Republic of)

Photodynamic therapy (PDT), which involves a generation of cytotoxic reactive oxygen species (ROS) by light activation of photosensitizers, has emerged as a promising minimally invasive therapeutic strategy for various types of cancer. However, because it inherently employs oxygen to generate ROS, hypoxia inevitably occurs during PDT. Cancer hypoxia is known to prevent effective cancer treatment, leading to cancer progression by promoting tumor metastasis, initiation of angiogenesis, and receptor upregulation. Herein, we design and synthesize biocompatible manganese ferrite nanoparticle-anchored mesoporous silica nanoparticles (MFMSNs) to overcome hypoxia, and consequently enhancing the therapeutic efficiency of PDT. By exploiting the continuously oxygen-generating property of manganese ferrite nanoparticles through Fenton reaction, MFMSNs successfully relieve hypoxia using a relatively small amount of nanoparticles and improve etherapeutic outcomes of PDT for tumors in vivo. In addition, it exhibits excellent T2 contrast effect in magnetic resonance imaging, allowing in vivo tracking of nanoparticles. These findings suggest a great potential of MFMSNs for effective theranostic agents in cancer therapy. (J. Kim et al. J. Am. Chem. Soc. 2017, 139, 10992-10995)