Enhanced In Vitro Photodynamic Performance under Hypoxia-Related Conditions by BP-Au@MnO2-Ce6 Nanocomposites

Abstract

As a widely used antitumor method, Photodynamic Therapy (PDT) mainly kills tumor cells through the toxic singlet oxygen (¹O₂) generated by the mixed action of photosensitizer, oxygen, and light source. However, the efficacy of PDT is significantly compromised by the unique microenvironment of solid tumors and the hydrophobicity of photosensitizers. Herein, BP-Au@MnO₂-Ce6 nanocomposites based on black phosphorus nanosheets (BPNS) are designed to overcome these limitations and improve the PDT effect. In the nanocomposites, BPNS with excellent optical properties can successfully load Au nanoparticles and photosensitizer Ce6 after PEI modification, thus achieving high light energy absorption and conversion efficiency in PDT. MnO₂ could effectively decompose endogenous H₂O₂ into oxygen to provide substrate for PDT, and react with highly active GSH to reduce its consumption of ¹O₂. The experiment shows that BP-Au@MnO₂-Ce6 nanocomposites could achieve efficient oxygen generation, GSH consumption, and singlet oxygen generation. Moreover, the nanocomposites exhibit good biocompatibility and can effectively inhibit tumor cell growth by generating toxic singlet oxygen in both normal and hypoxic environments, demonstrating their strong PDT effect.