MXene Quantum Dot Nanosensors for Food Safety: Structure–Function Relationships, Sensing Mechanisms, and Real‐World Deployment Challenges

ABSTRACT

MXene quantum dots (MQDs) have attracted increasing research interest as sensing materials because their quantum‐confined electronic structure and tailorable surface functionalities enable diverse signal transduction pathways suitable for analytical applications. Ensuring food safety requires rapid and reliable detection of toxic residues, including heavy metals, biogenic amines, and antibiotic contaminants, particularly within complex matrices where conventional methods remain limited. This review provides a critical analysis of MQD‐based nanosensors, emphasizing the structure–function relationships that govern sensing performance. The roles of quantum confinement, defect engineering, and surface terminations in modulating electronic properties, interfacial interactions, and signal transduction are systematically examined. Key sensing mechanisms, including inner filter effects, charge transfer, and analyte coordination, are discussed in relation to physicochemical characteristics and matrix conditions. Special attention is given to interfacial chemistry as a determinant of selectivity and signal fidelity in real food systems. Furthermore, multifunctional platforms such as dual‐mode fluorescence/colorimetric sensors and hybrid architectures are evaluated in terms of performance and trade‐offs. Beyond laboratory sensitivity, challenges related to reproducibility, stability, cross‐reactivity, and scalability are critically addressed. This work provides a framework linking nanoscale design to real‐world deployment, guiding the development of robust MQD‐based food safety sensors.