Engineering of upconversion carbon dots/metal-organic frameworks “Peeled Pitaya-Like” heterostructure for mitochondria-targeted photodynamic therapy

Developing of near-infrared (NIR) light triggered metal–organic frameworks (MOFs) nano-photosensitizers (nPSs) is highly desirable for photodynamic therapy (PDT) owing to its promising properties. Herein, we designed a mitochondria-targeted, 808 nm near-infrared (NIR) light-triggered upconversion carbon dots (CDs) coordinated porphyrinic MOFs (PCDs) nPSs for enhanced PDT. The system was fabricated through incorporation of sufficient ultrasmall CDs into the nanopores as well as the surface of porphyrinic porous MOFs to construct a peeled pitaya-like heterostructure, which was further functionalized with mitochondria-targeted moieties of triphenylphosphines (TPPs), termed PCDTs, for enhanced PDT. The upconversion CDs act as tremendous “antennas” to efficiently absorb NIR laser, and the tight coupling between the CDs and porphyrin in MOFs, greatly shortened the distance between the two components and improved the efficiency of the energy transfer from the CDs to porphyrinic MOFs, thus yielded a sharply enhanced 1O2 generation capability. The mitochondria-targeted ability further enhanced the ROS oxidative stress, accelerated dysfunction of mitochondria, and induced intrinsic apoptosis. Excellent anticancer ability was demonstrated by the in vitro cancer cells killing and in vivo suppression of tumor growth. This work presents a novel engineered heterostructure to combat the current limitation of MOF in PDT.