Metal nanozyme sensors with different modes: biomedical applications and research advances

In recent years, with the continuous advancement of nanotechnology, nanozymes have demonstrated tremendous potential in biomedical applications. By mimicking the catalytic activities of biological enzymes such as oxidases, peroxidases, and superoxide dismutases, nanozymes can be employed to detect various analytes, enabling their application in sensors. In the research of nanozymes, owing to their unique electronic structures and abundant surface active sites, endow metal nanozymes with both tunable high activity and strong stability. They can not only efficiently mimic the catalytic functions of various natural enzymes such as peroxidases, oxidases, and superoxide dismutases, but some types also exhibit high catalytic efficiency, even surpassing the natural enzymes themselves. This ability to mimic enzymatic activity endows nanozymes with distinctive properties. Signal conversion modes for metal nanozymes encompass multiple forms, including colorimetric, electrochemical, Surface-Enhanced Raman Scattering, and fluorescent detection. Herein, this review categorizes metal nanozyme sensors with different sensing modes into three major types: single-mode, dual-mode, and multi-mode. It summarizes the application potential of various sensor modes in scenarios such as biomarker detection, pathogen screening, and disease diagnosis, while analyzing current challenges including catalytic specificity and mode-to-mode synergy. Furthermore, this review explores the core challenges confronting metal nanozyme sensors and outlines future development directions, providing insights for the research and development of novel sensing technologies and their biomedical applications.