Carbon quantum dot fluorescent probes for food safety detection: Progress, opportunities and challenges

As a new photoluminescent nanomaterial, carbon quantum dots (CDs) have great potential in the detection of food ingredients and contaminants, owing to its merits of ease in preparation, good biocompatibility, adjustable modification, and various fluorescence response methods. However, since the rules of CDs in detecting different substances are rarely summarized by existing reports, the design of probes is blind in most cases. In this review, CDs are introduced, and the synthesis methods and optical properties of CDs are discussed. Fluorescence response mechanism of CDs in the detection of metal ions, drugs, food additives, bacteria, and nutrients has been analyzed and compared. As a result, design methods of CDs probes are divided into three, and introduction of functional groups on the surface of CDs was confirmed to be the core of design. Intermolecular interactions that different target substances tend to occur are summarized, which determines the choice of carbon source and synthesis method. Advantages, weaknesses and development trends of CDs fluorescence detection in food safety are discussed.