Self-Illuminating Copper-Luminol Coordination Polymers for Bioluminescence Imaging of Oxidative Damage

Timely detection of reactive oxygen species (ROS) accumulated during inflammation is essential for an early disease diagnosis. Compared to fluorescence probes with limited sensitivity and accuracy, chemiluminescence (CL) imaging offers the potential for highly sensitive molecular visualization of ROS by minimizing background interferences. However, the development of bright and easily manufacturable CL probes for ROS imaging remains challenging. In this study, a novel chemiluminescent nanoprobe named Cu-Lum@NPs for ROS imaging in inflammation was synthesized by using a one-step solvothermal method. The Cu-Lum@NPs, which are composed of coordination polymers containing copper ions and luminol (Lum), demonstrate intrinsic peroxidase-like activity that relies on Cu(I) as the catalytic active center to initiate the Fenton reaction. This catalytic process facilitates the decomposition of hydrogen peroxide (H₂O₂) into hydroxyl radicals (•OH) and superoxide anion radicals (O₂^•-), leading to the oxidation of Lum and inducing strong luminescence. Cu-Lum@NPs, displaying nanozyme characteristics, were observed to accelerate and enhance the ROS-responsive luminescence (10-1600-fold in solution and over 100-fold in neutrophils) and notably extend persistent luminescence. The Cu-Lum@NPs allowed for CL imaging of endogenous ROS in living cells and animals with an outstanding signal-to-noise ratio exceeding 96 and facilitated oxidative damage luminescence imaging for tissue-specific detection. The study presents Cu-Lum@NPs, a highly sensitive and easily manufacturable chemiluminescent nanoprobe for ROS imaging both in vitro and in vivo, exhibiting enhanced luminescence and prolonged persistence for ROS-related disease detection.