Detection of pathogenic bacteria with nanozymes-based colorimetric biosensors: Advances, challenges and future prospects

The prompt identification of foodborne pathogens is essential for safeguarding food safety and reducing financial repercussions. Nanozymes, characterized as nanomaterials exhibiting enzyme-like activity, are increasingly emerging as viable alternatives to natural enzymes as a result of their benefits like flexible design, regulated catalytic activity, good biocompatibility and high stability. The remarkable catalytic function of nanozymes has led to their extensive utilization in the development of colorimetric biosensors. Colorimetric sensors offer numerous advantages, including naked-eye visibility, ease of operation, portability, and high sensitivity. They have emerged as a potent and efficient tool for rapid detection, enabling the development of innovative colorimetric sensing strategies through the integration of nanozymes with colorimetric sensors. In this review, the recent advancements in nanozyme research and its utilization in colorimetric biosensing of pathogenic bacteria are analyzed. Firstly, nanozymes are presented in a systematic classification based on various nanomaterials, and their characteristics are elaborated upon in detail. Following this, the study centers on examining the construction approaches of nanozymes exhibiting peroxidase (POD), oxidase (OXD), superoxide dismutase (SOD), and catalase (CAT) activities for colorimetric biosensing of diverse pathogenic bacteria. Finally, the present challenges and future prospects concerning the enhanced utilization of nanozymes in colorimetric biosensors are deliberated in the last section.