Intraparticle Energy Level Alignment of Semiconducting Polymer Nanoparticles to Amplify Chemiluminescence for Ultrasensitive In Vivo Imaging of Reactive Oxygen Species

Detection of reactive oxygen species (ROS), a hallmark of many pathological processes, is imperative to understanding, detection and treatment of many life-threatening diseases. However, methods capable of real-time in situ imaging of ROS in living animals are still very limited. We herein report the development and optimization of chemiluminescent semiconducting polymer nanoparticles (SPNs) for ultrasensitive in vivo imaging of hydrogen peroxide (H2O2). The chemiluminescence is amplified by adjusting the energy levels between the luminescence reporter and the chemiluminescence substrate to facilitate intermolecular electron transfer in the process of H2O2-activated luminescence. The optimized SPN can emit chemiluminescence with the quantum yield up to 2.30 × 10–2 einsteins/mol and detect H2O2 down to 5 nM, which substantially outperforms the previous probes. Further doping of this SPN with a naphthalocyanine dye creates intraparticle chemiluminescence resonance energy transfer (CRET), leading to the near...