Development of an Au-anchored Fe Single-atom nanozyme for biocatalysis and enhanced tumor photothermal therapy

Near-infrared light-induced photothermal therapy (PTT) can achieve effective tumor ablation, but the associated hyperthermic temperatures result in off-target inflammatory damage to proximal tissues. Therefore, killing the tumor at a lower temperature is vital to improving the clinical effect of PTT. In this study, an Au-integrated Fe single-atom nanozyme (FeSAzyme) was developed through the immobilization of an ultrasmall Au nanozyme within a metal-organic framework via an in situ reduction approach. The nanozyme was found to exhibit favorable glucose oxidase- (GOD) like activity and photosensitizing properties to better achieve low-temperature PTT. The Au-carbon nanozyme was able to markedly inhibit tumor growth both in vitro and in vivo due to its GOD-like activity and enhanced photodynamic and photothermal properties. In addition, the integration of the Au nanozyme enhanced the FeSAzyme's peroxidase activity and catalyzed endogenous H2O2 species to generate reactive oxide species, thereby facilitating chemodynamic therapy. Furthermore, its integration markedly enhanced the PTT performance of the FeSAzyme, which achieved pronounced synergistic anti-tumor efficacy. The enzymatic activity and photothermal/photosensitive properties of the Au-FeSAzyme may help to overcome traditional therapeutic limitations, indicating its potential for catalytic cascade nanozymes in biomedical applications.