Biomimetic O2-Evolving metal-organic framework nanoplatform for highly efficient photodynamic therapy against hypoxic tumor.

Improving the supply of O2 and the circulation lifetime of photosensitizers for photodynamic therapy (PDT) in vivo would be a promising approach to eliminate hypoxic tumors. Herein, by taking advantage of the significant gas-adsorption capability of metal-organic frameworks (MOFs), a biomimetic O2-evolving photodynamic therapy (PDT) nanoplatform with long circulating properties was fabricated. Zirconium (IV)-based MOF (UiO-66) was used as a vehicle for O2 storing, then conjugated with indocyanine green (ICG) by coordination reaction, and further coated with red blood cell (RBC) membranes. Upon 808 nm laser irradiation, the initial singlet oxygen (1O2) generated by ICG would decompose RBC membranes. At the same time, The photothermal property of ICG could facilitate the burst release of O2 from UiO-66. Subsequently, the generated O2 could significantly improve the PDT effects on hypoxic tumor. Owing to the advantages of long circulation and O2 self-sufficient, the designed nanotherapeutic agent can improve the efficiency of treatment against hypoxia tumor via PDT. Hence, this study presents a new paradigm for co-delivery of O2 and photosensitizers, and provides a new avenue to eliminate hypoxic tumors.