Carbon dots as a multifunctional additive: Preparation methods, characteristics, application and prospects in food packaging and preservation

Carbon dots (CDs), as nanomaterials with dimensions less than 10 nm, exhibit broad application prospects in fields such as bioimaging, food detection, functional packaging, and biomedicine, owing to their unique optical properties, excellent biocompatibility, and low-cost tunability. This review systematically states the preparation processes, physicochemical properties, and functional characteristics of CDs, and delves into their biological safety and toxicological characteristics. Research indicates that the toxic effects of CDs are closely related to their size, surface modification, surface charge, and exposure dose. Both in vitro cell experiments and in vivo animal model studies have confirmed that high concentrations of CDs may induce adverse reactions such as oxidative stress, apoptosis, and tissue damage. However, potential risks can be effectively mitigated through raw material optimization, surface engineering optimization, and composite modification strategies. This paper also analyzes the major challenges of CDs in migration behavior of food contact materials, toxicological evaluation, standard supervision and industrialization, and discusses the prospects for their safe and standardized development in the food field. It is concluded that despite outstanding advantages in food packaging and preservation, CDs still face biosafety and industrialization bottlenecks. Establishing a full-life cycle safety evaluation system and improving risk assessment methods are critical for their industrial transformation.