Synergistic integration of CRISPR/Cas and nanozymes in next-generation biosensors for ultrasensitive bacterial detection.

The rapid and accurate detection of pathogenic bacteria is paramount for global public health, food safety, and clinical diagnosis. While conventional methods face limitations in speed, sensitivity, and field-deployability, biosensors incorporating CRISPR/Cas systems and nanozymes have emerged as a transformative solution. This review provides a comprehensive analysis of this cutting-edge synergy. We first elucidate the fundamental mechanisms, highlighting the unparalleled programmability and specific nucleic acid cleavage activity of Class II CRISPR/Cas systems (e.g., Cas12, Cas13), and the robust, cost-effective, and tunable catalytic properties of various nanozymes (e.g., metal-based, MOF-derived). The core innovation lies in their integration: the CRISPR/Cas system acts as a highly specific molecular recognition unit, whose activation triggers the signal amplification function of nanozymes. We critically examine recent advancements in biosensing platforms that leverage this combination for the detection of diverse bacteria (e.g., Salmonella, Legionella, drug-resistant strains) via multiple readouts (colorimetric, fluorescent, electrochemical). The results demonstrate the exceptional sensitivity (often reaching attomolar or single CFU levels) and versatility achieved by these platforms. Finally, the current challenges, such as signal stability and the demand for multiplex detection, are discussed. Future development directions are also prospected, including the development of extraction-free detection methods, the fabrication of renewable sensors to achieve true point-of-care testing, and the design of novel nanozymes with higher specificity. This review not only summarizes the state-of-the-art but also charts a course for the next generation of intelligent, rapid, and accessible diagnostic tools.