Phosphonated Heptamethine Dye Alleviates Radiation‐Induced Bone Loss

Abstract High levels of reactive oxygen species (ROS) are closely associated with osteoclast formation and function, resulting in bone loss. Herein, a novel ROS scavenger, named IR‐ALN, based on the heptamethine cyanine (Cy7) dyes is reported. IR‐ALN not only retains the inherent near‐infrared (NIR) fluorescence imaging and ROS scavenging activity of Cy7 dyes, but is also selectively absorbed by the osteoclast precursor cells, inhibiting osteoclast differentiation and bone resorption activity. Moreover, IR‐ALN exhibits bone‐targeted accumulation in a dose‐dependent manner and effectively alleviates bone and trabecular volume loss caused by X‐ray. The results suggest that IR‐ALN is a potential radioprotective agent that prevents radiation‐induced bone loss. Furthermore, the design strategy for IR‐ALN can be used as a reference for the development of new radioprotective agents.