A Photothermal/Chemodynamic Combined Therapy Nanoplatform AuNRs@FQ Capable of Generating Reactive Oxygen Species and Inhibiting Tumors

The advancement of catalytic therapy is often limited by the insufficient reaction rates, and the treatment efficacy is less than ideal. It is necessary to improve the kinetics of catalytic reactions to enhance the performance of the therapy. Here, we reported a nanoplatform AuNRs@FQ that utilized the photothermal heating to boost the catalytic activity while simultaneously employing photothermal treatment (PTT) and chemodynamic therapy (CDT) for breast cancer intervention. In this system, the gold nanorods (AuNRs) with the excellent near-infrared-II (NIR-II) photothermal conversion are covered by the Fe3+–quercetin (FQ) metal–phenolic framework (MPN). The MPN disintegrates in a pH-sensitive manner within the mildly acidic tumor microenvironment, concurrently releasing Fe3+ ions and quercetin (Que). The released Fe3+ can scavenge the intracellular glutathione (GSH) to disrupt the cellular antioxidant defense system and is reduced to Fe2+. Subsequently, Fe2+ catalyzes the decomposition of hydrogen peroxide (H2O2) to generate highly reactive oxygen species (ROS), specifically hydroxyl radicals (·OH), via the Fenton reaction. As a natural chemotherapeutic compound, Que also increases the concentration of intracellular ROS, thus enhancing the cytotoxic effect of CDT. The AuNR nanomaterial can produce the quick production of the localized elevated temperature when irradiated by 1064 nm laser light, which improves the catalytic performance and the CDT result and delivers the effective PTT. Both in vitro and in vivo, it was also shown that AuNRs@FQ remarkably suppressed the growth of the breast cancer cells and the development of the tumor. This study presents a NIR-II photothermal amplification approach using the MPN-mediated CDT and combining the photothermal and catalytic therapies to greatly boost the ROS generation and to accomplish a potent combined treatment.