In vivo therapeutic response monitoring by a self-reporting upconverting covalent organic framework nanoplatform

The real-time and in situ monitoring of reactive oxygen species (ROS) generation is critical for minimizing the nonspecific damage derived from the high doses of ROS required during the photodynamic therapy (PDT) process. However, phototherapeutic agents that can generate ROS-related imaging signals during PDT are rare, hampering the facile prediction of the future therapeutic outcome. Herein, we develop an upconverting covalent organic framework (COF) nanoplatform via a core-mediated strategy and further functionalized it with a singlet oxygen reporter for the efficient near-infrared activated and in situ self-reporting of PDT. In this work, the COF photodynamic efficacy is greatly improved (12.5 times that of irregular COFs) via tailoring the size. Furthermore, this nanoplatform is able to not only produce singlet oxygen for PDT, but it can also emit singlet oxygen-correlated luminescence, allowing the real-time and in situ monitoring of the therapeutic process for cancer cells or solid tumors in vivo via near-infrared luminescence imaging. Thus, our core-mediated synthetic and size-tailored strategy endows the upconverting COF nanoplatform with promising abilities for high-efficacy, deep-tissue, precise photodynamic treatment.