Chemo-photothermal synergy ignites antitumor immunity via ferroptosis

Docetaxel (Doc), a widely used chemotherapeutic agent, was limited by suboptimal therapeutic efficacy and dose-limiting systemic toxicity due to the insufficiency of hydrophilicity and tumor-targeting specificity. To address this limitation, we developed an amphiphilic ferrocene-based polymer, PPEGMA-b-PFMMA (PF), to co-encapsulate Doc and the photosensitizer IR808, forming photothermally responsive nanoparticles (NPs) termed P8D NPs. P8D NPs significantly improved the aqueous stability and tumor-specific accumulation of both agents by leveraging a hydrogen peroxide (H₂O₂)-triggered drug release mechanism within the tumor microenvironment. Under near‑infrared (NIR) irradiation, P8D NPs generated substantial heat and a burst of reactive oxygen species (ROS), promoting NPs disintegration and drug release. Mechanistically, Doc induced nuclear to cytoplasmic translocation of HMGB1, while photothermal/photodynamic therapy (PTT/PDT) facilitated the extracellular release of damage-associated molecular patterns (DAMPs) and tumor-associated antigens via ferroptosis and cell membrane rupture. Together, these actions enhanced dendritic cells (DCs) maturation, antigen presentation and cytotoxic CD8⁺ T cell infiltration in tumor, thereby effectively reversing the immunosuppressive tumor microenvironment. Remarkably, this combination strategy not only inhibited the growth of distant tumors but also established long-term anti-tumor immunological memory to prevent recurrence. This study demonstrates that ferrocene-based nanocarrier-mediated PTT/PDT synergizes with Doc to reactivate antitumor immunity through ferroptosis-induced immunogenic cell death (ICD).