ICG/MnO2-HFn-mPEG-DSPE-Lip enhances the anticancer activity of ICG phototherapy.

Hypoxia poses a significant challenge to the efficacy of photodynamic therapy (PDT) for cancer treatment. This study aims to design and synthesize PEGylated liposomes encapsulating MnO₂, indocyanine green (ICG), and H-chain ferritin (HFn) to potentially address hypoxia and enhance the therapeutic outcomes of PDT. PEGylated liposomes (ICG/MnO₂-HFn-mPEG-DSPE-Lip) were constructed with a rod-like structure, incorporating MnO₂ as a hypoxia-modulating agent and ICG as a photosensitizer. The drug loading capacity, stability and safety of liposomes were characterized. Singlet oxygen quantum yield (ΦΔ) was measured under simulated tumor microenvironment conditions. In vitro phototoxicity was evaluated using A549 human lung adenocarcinoma cells. Liposomes have a high drug loading capacity, good biocompatibility and good long-term stability. Under tumor-simulated conditions, ΦΔ was significantly improved, increasing from 0.210 for free ICG to 0.507. The liposomes demonstrated remarkable phototoxic effects on A549 cells (90.5% cell death under combined PDT/PTT vs. 15% for free ICG). This nanoplatform proposes a novel strategy to overcome hypoxia-induced PDT resistance, and the enhanced efficacy may be attributed to the increased oxygen supply mediated by MnO2 carried by HFn. These findings provide important insights for the development of next-generation therapeutic systems targeting tumor hypoxia.