A hyperthermia-enhanced nanocatalyst based on asymmetric Au@polypyrrole for synergistic cancer Fenton/photothermal therapy

Abstract

The specific tumor microenvironment is a conducive breeding ground for malignant tumors, favoring their survival, rapid proliferation, and metastasis, which is also an inevitable obstacle to tumor treatment, particularly for catalytic therapy. To address this issue, a hyperthermia-enhanced nanocatalyst (AuP@MnO₂) consisting of an asymmetric Au@polypyrrole core and a MnO₂ shell is constructed for synergistic cancer Fenton/photothermal therapy. In an ultra-short reaction time (15 min), the innovative introduction of a new oxidizer, tetrachloroauric acid trihydrate, not only successfully initiates the oxidative polymerization of pyrrole monomer while reducing itself to cubic Au, but also accelerates the polymerization process by supplying protic acid. After MnO₂ coating, AuP@MnO₂ catalyzes the conversion of antioxidant GSH and excess H₂O₂ into GSSG and ˙OH through Mn²⁺/Mn⁴⁺ ion couples, leading to oxidative damage of tumor cells. More importantly, after 1064 nm laser irradiation, more extreme oxidative imbalance and cell death are demonstrated in this work under the combined effect of photothermal and catalytic therapy, with insignificant toxicity to normal cells. This work develops an efficient one-step synthesis method of asymmetric Au@polypyrrole and provides constructive insight into its oxidative stress-based antitumor treatment.