Chemodynamic therapy combined with endogenous ferroptosis based on "sea urchin-like" copper sulfide hydrogel for...

Chemodynamic therapy (CDT) is a promising strategy for cancer treatment, however, its application is restricted by low hydrogen peroxide (H₂O₂) concentration, insufficient reactive oxygen species (ROS) generation, and high glutathione (GSH) levels. Here, we developed an injectable thermosensitive hydrogel (DSUC-Gel) based on "sea urchin-like" copper sulfide nanoparticles (UCuS) loaded with dihydroartemisinin (DHA) and sulfasalazine (SAS) to overcome these limitations of CDT. DSUC was cleaved to release DHA, SAS and Cu²⁺ under acidic tumor microenvironment to enhance CDT. DHA with peroxide bridge responded to intracellular Fe²⁺ to alleviate H₂O₂ deficiency. SAS prevented GSH synthesis by targeting SLC7A11 and inhibited glutathione peroxidase (GPX4) activity to induce endogenous ferroptosis. ROS produced by Fenton-like reaction of Cu²⁺ promoted lipid peroxidation (LPO) accumulation to promote ferroptosis. Enhanced CDT and ferroptosis induced immunogenic cell death (ICD), promoted dendritic cells (DCs) maturation and cytotoxic T lymphocytes (CTLs) infiltration. As a result, DSUC-Gel significantly inhibited tumor growth both in vitro and in vivo. Our study provides a novel approach for enhancing anti-tumor efficacy by combining CDT, endogenous ferroptosis and ICD.