3D DNA walker-based biosensors: From programmable trajectory to detection of foodborne pathogens

3D DNA walker, characterized by its programmable molecular recognition capability, efficient signal amplification, and precise track controllability, has emerged as a novel intelligent sensing element for constructing highly sensitive biosensors to detect foodborne pathogens. This review systematically summarizes recent advances in the application of 3D DNA walkers for foodborne pathogen detection, with a specific focus on construction strategies, driving mechanisms, and the design and application of corresponding biosensors. First, the two core construction strategies of 3D DNA walkers are thoroughly analyzed from the perspective of track carrier materials, covering functionalized carriers based on nanomaterials and structurally precise tracks constructed on nucleic acid scaffolds. Subsequently, five major driving mechanisms are investigated in depth, including nuclease activation, DNAzyme-driven cleavage, strand displacement-mediated dynamic regulation, CRISPR/Cas-mediated cleavage, and environmental factor responsiveness, thereby comprehensively elucidating the motion control principles underlying the 3D DNA walker operation. Furthermore, the development of optical, electrochemical, and multi-mode biosensors based on 3D DNA walkers and their applications in detecting foodborne pathogens are systematically summarized. Finally, current limitations of the technology are discussed along with a forward-looking perspective on its future development. This review aims to provide theoretical insights for promoting the innovative development of 3D DNA walker technology and facilitate its large-scale application and technological breakthroughs in food safety monitoring and on-site rapid diagnostics.