Multifunctional nanozymes: Promising applications in clinical diagnosis and cancer treatment

Cancer remains one of the greatest challenges in modern medicine. Traditional chemotherapy drugs often cause severe side effects, including nausea, vomiting, diarrhea, neurotoxicity, liver damage, and nephrotoxicity. In addition to these adverse effects, high recurrence and metastasis rates following treatment pose significant challenges for clinicians. There is an urgent need for novel therapeutic strategies to improve cancer treatment outcomes. In this context, nanozymes-artificial enzyme mimetics-have attracted considerable attention due to their unique advantages, including potent tumor-killing effects, enhanced biocompatibility, and reduced toxicity. Notably, nanozymes can dynamically monitor tumors through imaging and tracing. The multifunctional nanozyme (MN) is a promising research focus, integrating multiple catalytic activities, signal enhancement, sensing capabilities, and diverse modifications within a single nanozyme system. MNs can selectively target tumor regions, facilitating synergistic effects with other cancer therapies while enabling real-time imaging and tumor tracking. In this review, we first categorize MNs based on their composition and structural characteristics. We then discuss the primary mechanisms by which MNs exert their anticancer effects. Additionally, we review three types of MN biosensors and four MN-based therapeutic approaches applied in cancer treatment. Finally, we highlight the current challenges in MN research and provide an outlook on future developments in this field.