Near‐Infrared II Nanoadjuvant‐Mediated Chemodynamic, Photodynamic, and Photothermal Therapy Combines Immunogenic Cell Death with PD‐L1 Blockade to Enhance Antitumor Immunity

The efficacy of immune checkpoint inhibition in inducing death of cancer cells is affected by the immunosuppressive "cold" tumor microenvironment, which results in a poor response by the patient's antitumor immune system. However, the immunomodulatory effects of immunogenic cell death in response to irritation by heat energy and reactive oxygen species (ROS) can switch the tumor microenvironment from "cold" to "hot." This study has developed a nanoadjuvant for immune therapy using iron tungsten oxide (FeWOx)-based nanosheets with surface PEGylation (FeWOx-PEG). This FeWOx-PEG nanoadjuvant serves as a chemodynamic reagent via the Fenton reaction and acts as a photosensitizer for photodynamic and photothermal therapy under near-infrared II laser irradiation; however, it could also be used to augment tumor-infiltrating T-cells and provoke a systemic antitumor immune response by combining the immunogenic cell death triggered by ROS and photothermal therapy with the immune checkpoint blockade. This research demonstrates that application of the FeWOx-PEG nanoadjuvant under the guidance of magnetic resonance/computed tomography/photoacoustic imaging can eliminate the primary tumor and suppress the growth of distant tumors.