Carbon dots probes: Structural & functional insights towards emerging food and agricultural applications

Carbon dots (C-dots or CDs) represent an emerging class of carbon-based nanomaterials with particle sizes typically below 10 nm, exhibiting exceptional physicochemical, photoluminescent, and catalytic properties. These versatile features make C-dots promising candidates for biosensing, bioimaging, drug delivery, Fig catalysis (catalysis using Fig trees/Ficus species extracts or enzymes), environmental remediation, and energy conversion applications. Heteroatom doping (with elements such as N, S, P, B, or metals) has been demonstrated to modulate the electronic structure, surface states, and bandgap of C-dots, leading to significant enhancements in their optical performance, quantum yield, and functional tunability. Such doped C-dots have opened new frontiers in food processing technologies, including quality assessment, contaminant detection, and nutrient tracking. This review comprehensively discusses the structural design, doping mechanisms, and synthetic strategies of organic- and inorganic-doped C-dots, with a focus on their multifunctional applications in the food industry. In this account, we describe recent progress in carbon dots, highlighting the structure-property and performance relationships, cross-linking-induced quantum dot luminance, and advancements in various field applications. In addition, highlight the different preparation of carbon dots and their applications in the detection of several ions, cell imaging, bio-imaging, and wastewater treatment. Furthermore, this article aims to highlight the potential of doped C-dots as efficient broad-spectrum quenching agents and to discuss future perspectives and challenges in integrating doped carbon nanostructures into next-generation food safety and nanotechnology platforms. Moreover, it highlights the latest applications of carbon dots across diverse fields, offering valuable insight into preparation methods and their influence on performance and applications. • Carbon dots in food & agriculture: a critical review of doping to tune structure and function. • C-dots transformed into multifunctional materials for diverse food-related applications. • Systematic overview of carbon dot synthesis, structural modifications, and doping mechanisms. • Novel pathways for using doped C-dots in biosensing, preservation, quality monitoring, and food safety.