Metal-organic framework (MOF)-based sensors for exogenous contaminants in food: Mechanisms, advances, and prospects

The global food safety issues caused by exogenous contaminants have posed increasing threat to public health. Reliable sensing approach with excellent performance for the sensitive detection of these contaminants is in great necessity and urgency in food safety control. Metal-organic frameworks (MOFs), a new class of porous crystal materials with fascinating merits of tunable compositions and structures, high porosity, and large and easy-to-functionalize surfaces, have been extensively developed to construct diverse sensors for food safety measurement. The relevant publications have increased exponentially, attracting significant research attention. Therefore, this review summarized the main types of emerging MOFs and the current state-of-the-art synthetic strategies. The MOF-based optical sensors developed over the past five years, such as the colorimetric (CM), fluorescent (FL), electrochemiluminescent (ECL), and surface-enhanced Raman spectroscopy (SERS) series, and electrochemical (EC) sensors were comprehensively discussed regarding their construction, sensing mechanisms, and real-world application for exogenous contaminants including mycotoxins, pesticide residues, and heavy metals in food. Besides highlighting the recent advances and advantages of these MOF-based sensors, their current challenges and future prospects were systematically discussed. This review aimed to provide several beneficial insights regarding the coordination chemistry and performance of MOFs and facilitate the exploration of MOF-based sensing platforms for more hazardous contaminants to guarantee food safety.