Facile Phototherapeutic Nanoplatform by Integrating a Multifunctional Polymer and MnO2 for Enhancing Tumor Synergistic Therapy

: Recent studies indicate that the synergistic phototherapy (SPT) process can simultaneously generate heat for photothermal therapy (PTT) and singlet oxygen (1 O2 ) for photodynamic therapy (PDT) to overcome the recurrence of tumors. However, the hypoxic environment in tumors seriously limits the therapeutic effect of the oxygen-dependent PDT, leading to the domination of PTT in the SPT process. Therefore, it is urgent to develop a novel SPT platform for overcoming hypoxia in tumors and improving the therapeutic effect of both PTT and PDT. In this work, a novel phototherapeutic platform based on a nanocomposite of aza-BODIPY/manganese dioxide (MnO2 ) is developed via simple electrostatic self-assembly. In this design, MnO2 nanosheets, which could produce heat and catalyze endogenous hydrogen peroxide (H2 O2 ) to generate oxygen, are prepared as a nanocarrier. After being coated with the as-prepared water-soluble aza-BODIPY-based polymer (PPAIB), the obtained MnO2 @PPAIB performs as a smart phototherapeutic agent for enhancing the efficiency of both PTT and PDT. More importantly, compared to PPAIB, MnO2 @PPAIB generates more heat and reactive oxygen species to realize the enhanced therapy effects of PTT and PDT. Hence, this work provides a new method to enhance the therapeutic efficacy of SPT by using a polymer/MnO2 nanoplatform to improve the oxygen concentration and produce more heat.