A bacterial bimetallic nanozyme hybrid strategy for enhancing radiotherapy

Cancer treatment using bacteria has gained attention due to the ability of bacteria to selectively colonize low-oxygen tumor regions, providing opportunities for targeted therapy and immune activation. Here, we report a probiotic-mediated hybrid system that combines Bifidobacterium infantis with a copper-hafnium bimetallic nanozyme. This system delivers the nanozyme to tumors and stimulates immune responses. The nanozyme converts excess hydrogen peroxide in tumors into reactive oxygen species and oxygen, enhancing the effects of radiotherapy. Hafnium ions increase X-ray energy deposition, causing DNA damage and improving therapeutic outcomes. Moreover, the system induces immunogenic cell death and activates a key immune signaling pathway, generating a strong antitumor immune response. This approach effectively integrates bacterial targeting, high atomic number nanomaterials, and enzymatic catalysis, offering a strategy to improve radiotherapy and overcome the limitations of conventional treatments.