Au25 cluster functionalized metal–organic nanostructures for magnetically targeted photodynamic/photothermal therapy triggered by single wavelength 808 nm near-infrared light

Abstract

Near-infrared (NIR) light-induced cancer therapy has gained considerable interest, but pure inorganic anti-cancer platforms usually suffer from degradation issues. Here, we designed metal–organic frameworks (MOFs) of Fe₃O₄/ZIF-8-Au₂₅ (IZA) nanospheres through a green and economic procedure. The encapsulated Fe₃O₄ nanocrystals not only produce hyperthemal effects upon NIR light irradiation to effectively kill tumor cells, but also present targeting and MRI imaging capability. More importantly, the attached ultrasmall Au₂₅(SR)₁₈⁻ clusters (about 2.5 nm) produce highly reactive singlet oxygen (¹O₂) to cause photodynamic effects through direct sensitization under NIR light irradiation. Furthermore, the Au₂₅(SR)₁₈⁻ clusters also give a hand to the hyperthemal effect as photothermal fortifiers. This nanoplatform exhibits high biocompatibility and an enhanced synergistic therapeutic effect superior to any single therapy, as verified by in vitro and in vivo assay. This image-guided therapy based on a metal–organic framework may stimulate interest in developing other kinds of metal–organic materials with multifunctionality for tumor diagnosis and therapy.