Ultrathin Cu-TCPP MOF nanosheets: a new theragnostic nanoplatform with magnetic resonance/near-infrared thermal imaging for synergistic phototherapy of cancers.

Nanostructures based on metal-organic frameworks (MOFs) have promising potential as theragnostic nanoplatforms for phototherapy of cancer cells. However, the MOFs alone are seldom reported to be used as photothermal agents mainly due to their poor near-infrared (NIR) light absorption. Ultrathin copper-tetrakis (4-carboxyphenyl) porphyrin (Cu-TCPP) MOF nanosheets were prepared by a facile solvothermal route. The photothermal therapy (PTT), photodynamic therapy (PDT), and -weighted magnetic resonance (MR) imaging capabilities and the high biocompatibility of these composite nanosheets were evaluated as well as in a mouse tumor model. The ultrathin Cu-TCPP MOF nanosheets exhibited 1) strong NIR absorption because of the d-d energy band transition of Cu and the ultrathin characteristic translating into excellent photothermal performance, 2) ability to produce singlet oxygen because of the inherent characteristic of TCPP, and 3) capability for MR imaging because of the unpaired 3 electrons of copper. Our study demonstrated that the Cu-TCPP MOF nanosheets are a promising phototherapy nanoplatform with the synergistic ability for PTT and PDT of cancer, guided by MR and infrared thermal imaging.