Photothermal Therapy Nanomaterials Boosting Transformation of Fe(III) into Fe(II) in Tumor Cells for Highly Improving Chemodynamic Therapy

Chemodynamic therapy based on Fe2+-catalyzed Fenton reaction holds great promise in cancer treatment. However, low-produced hydroxyl radicals in tumor cells constitute its severe challenges because of the fact that Fe2+ with high catalytic activity could be easily oxidized into Fe3+ with low catalytic activity, greatly lowering Fenton reaction efficacy. Here, we codeliver CuS with the iron-containing prodrug into tumor cells. In tumor cells, the overproduced esterase could cleave the phenolic ester bond in the prodrug to release Fe2+, activating Fenton reaction to produce the hydroxyl radical. Meanwhile, CuS could act as a nanocatalyst for continuously catalyzing the regeneration of high-active Fe2+ from low-active Fe3+ to produce enough hydroxyl radicals to efficiently kill tumor cells as well as a photothermal therapy agent for generating hyperthermia for thermal ablation of tumor cells upon NIR irradiation. The results have exhibited that the approach of photothermal therapy nanomaterials boosting tran...