Polydopamine-Based Light Responsive Nanoparticles with Magnetic Resonance Imaging Capabilities for Breast Cancer Photodynamic/Photothermal Therapy Combination Therapy.

Polydopamine (PDA)-based nanoparticles demonstrate significant potential for breast cancer photodynamic therapy and photothermal therapy, owing to their nanoscale dimensions and superior biocompatibility. However, their efficacy is limited by the tumor microenvironment and shallow near-infrared (NIR) laser penetration. In this study, we developed a novel nanoparticle system, MnO/Ce6@PDA, with a PDA core loaded with photosensitizer chlorin e6 (Ce6) and coated with manganese oxide (MnO) for synergistic PTT/PDT. Utilizing the photoresponsive properties of PDA and Ce6, along with the oxidative capacity of MnO, the nanoparticles demonstrated strong photothermal conversion and catalytic activity. Coating with tumor cell membrane (MnO/Ce6@PDA@CCM) preserved adhesion proteins such as integrins and cadherins, enabling homotypic targeting and tumor-specific accumulation. Under NIR laser irradiation at different wavelengths, the nanoparticles generate significant amounts of reactive oxygen species and singlet oxygen, resulting in the death of tumor cells via mitochondrial and cell membrane damage. The release of Mn2+ ions during tumor microenvironment-responsive degradation not only enhanced T1-weighted magnetic resonance contrast, but also potentiated chemodynamic therapy via Fenton-like reactions, enabling real-time imaging-guided combinatorial antitumor efficacy.