Biomineralization Synthesis of the Cobalt Nanozyme in SP94-Ferritin Nanocages for Prognostic Diagnosis of Hepatocellular Carcinoma

Nanomaterials with intrinsic enzyme-like activities (nanozymes) have emerged as promising agents for cancer theranostics strategies. However, size-controllable synthesis of nanozymes and their targeting modifications are still challenging. Here, we report a monodispersed ferritin-based cobalt nanozyme (HccFn(Co3O4)) that specifically targets and visualizes clinical hepatocellular carcinoma (HCC) tissues. The cobalt nanozyme is biomimetically synthesized within the protein shell of the HCC-targeted ferritin (HccFn) nanocage, which is enabled by the display of HCC cell-specific peptide SP94 on the surface of ferritin through a genetic engineering approach. The intrinsic peroxidase-like activity of HccFn(Co3O4) nanozymes catalyzes the substrates to make color reaction to visualize HCC tumor tissues. We examined 424 clinical HCC specimens and verified that HccFn(Co3O4) nanozymes distinguish HCC tissues from normal liver tissues with a sensitivity of 63.5% and specificity of 79.1%, which is comparable with that of the clinically used HCC-specific marker a fetoprotein. Moreover, the pathological analysis indicates that the HccFn(Co3O4) nanozyme staining result is a potential predictor of prognosis in HCC patients. Staining intensity is positively correlated to tumor differentiation degree (P = 0.0246) and tumor invasion (P < 0.0001) and negatively correlated with overall survival (P = 0.0084) of HCC patients. Together, our study demonstrates that ferritin is an excellent platform for size-controllable synthesis and targeting modifications of nanozymes, and the HccFn(Co3O4) nanozyme is a promising reagent for prognostic diagnosis of HCC.