AuPt-loaded Fe-N-C flower-like nanocascade reactor with self-supplied reaction substrates and multiple enzyme activities for the study of hypoxic tumors.

When nano-enzymes are used in tumor therapy research, they usually exhibit only a single enzyme activity, which limits their therapeutic effect in hypoxic tumors. This paper designs a hyaluronic acid (HA)-modified Au-Pt-Fe trimetallic flower-like nanomaterial for tumor cascade catalysis integrated with low-temperature photothermal therapy. GOx activity exhibited by AuPt nanoparticles converts glucose in tumor cells into gluconic acid and H2O2. This process not only deprives tumor cells of their energy source but also produces H2O2. Iron single-atom nanomaterials can exhibit excellent CAT and POD activities, catalyzing H2O2 reactions in tumor cells. Among them, a portion of H2O2 is converted to O2 by the activity of nanozyme CAT, which is used to alleviate tumor tissue hypoxia and serve as a substrate for the GOx-like activity reaction of AuPt NPs. The H2O2 is continuously produced by the glucose catalytic reaction, and a portion of it can further decompose into toxic OH through POD activity, contributing to tumor cell destruction. The glucose-H2O2-O2 cycle reaction is realized, that is, the self-supply of H2O2 and O2 in the catalytic process within tumor cells. The introduction of AuPt nanoparticles enhances the photothermal conversion ability of the material. By using near-infrared light irradiation, mild-temperature photothermal therapy (m-PTT) can be achieved, which further improves the treatment effect while protecting surrounding tissues. This work expands the application of multi-metal nanomaterials in cascade catalysis combined with low-temperature photothermal therapy, providing a novel strategy for integrated tumor treatment.