A versatile Pt-Ce6 nanoplatform as catalase nanozyme and NIR-II photothermal agent for enhanced PDT/PTT tumor therapy

The hypoxic nature of solid tumors has a serious negative impact on oxygen-based photodynamic therapy. Pt nanoparticles as a carrier for catalase (CAT) nanoenzyme, a second near infrared (NIR-II) region photothermal transition agent (PTA) and dihydroporphyrin e6 (Ce 6). In this system, Pt-Ce 6 can continuously and stably decompose H2O2 into oxygen, thus reducing tumor hypoxia and improving the effectiveness of photodynamic therapy (PDT). With 650nm illumination, reactive oxygen species (ROS) produced by Ce 6 will reduce the mitochondrial membrane potential (MMP) to release cytochrome c (Cyt-c) from mitochondria into the cytoplasm, ultimately leading to mitochondria-mediated apoptosis during PDT. In addition, Pt-Ce 6 has good photothermal stability and high photothermal conversion efficiency (52.62%) in the NIR-II region. Pt-Ce 6 completely inhibited tumor growth and relapse in U14 tumor-bearing mice under laser irradiation. Therefore, the nanocomposite shows excellent PDT / photothermal therapy (PTT) synergistic performance both in vitro and in vivo.