Malignant tumor treatment remains a major challenge due to the limited precision and significant side effects. Copper-based single-atom nanozymes have shown promise for tumor microenvironment-responsive precision therapy, but their practical application is limited by weak substrate adsorption, difficulty in synthesizing low-coordination unsaturated structures, and limitations of conventional preparation methods. A research team has now successfully developed a coordination-unsaturated copper single-atom nanozyme. Their work is published in Advanced Functional Materials.