Independent and EfficientPyridone Scaffold: UniversalAfterglow Chemiluminescence Platform for High-Contrast Bioimaging

Abstract Organic afterglow chemiluminescence imaging holds great promise for high-contrast biomedical applications owing to its elimination of real-time excitation light and low biotoxicity. However, conventional molecular design strategies face significant challenges. Both integrated molecules and multicomponent physical hybrid systems suffer from inherent drawbacks, such as irreversible substrate consumption, emission blue-shift and inefficient energy transfer, which ultimately limit their performance and applications. To address these issues, we report an independent and efficient pyridone scaffold for constructing afterglow molecules. 2-pyridone was employed as a stable, nonconsumable substrate to prevent depletion and blue-shift, while covalent linkage with the relay unit ensured efficient intramolecular energy transfer. Based on this scaffold, a series of afterglow chemiluminescent molecules (RB-Py, BDP-Py, HC-Py, CS-Py, Cy-Py) were constructed. Upon encapsulation with Pluronic F127 to form nanoparticles, these molecules demonstrated excellent afterglow performance in PBS. An activatable afterglow chemiluminescence probe (HFO-NPs) was developed, which can simultaneously activate fluorescence and afterglow signals in the presence of peroxynitrite (ONOO–). Furthermore, we successfully applied it for the precise diagnosis of APAP-induced early liver injury and the visualization of ONOO– levels. Together, these findings establish a new paradigm for organic afterglow molecules and provide a powerful new platform for precise molecular sensing and disease diagnosis.