Carbon dot-integrated edible films: emerging synergies for advanced food packaging applications

The escalating global demand for safe, sustainable, and environmentally friendly food packaging has stimulated the research of edible films as potential alternatives to conventional plastics. However, the inherent disadvantages associated with biopolymers, such as poor mechanical properties, their high moisture sensitivities and the absence of significant bioactive properties, hamper the large-scale use of such films. Recently, carbon dots (CDs), a new type of carbon-based nanomaterial with excellent photoluminescence properties and tunable surface wall chemistry and biocompatibility, have gained popularity as multifunctional nanofillers to strengthen edible films. Their incorporation into protein-, polysaccharide-, and lipid-based edible films has been shown to effectively enhance antimicrobial action, antifungal activity, and antioxidant activity and, at the same time, enable real-time detection of food quality and spoilage biomarkers. This review critically analyzes synthesis methodologies, functional activity, and the route of action through which CDs confer high performance levels on edible films. It particularly focuses on antimicrobial/antifungal protection, antioxidant-induced shelf-life extension, intelligent packaging applications, and multifunctional composite systems. In addition, toxicological and safety concerns of edible films based on CDs are addressed, with implications and future perspectives of their industrial adaptation as the key concerns. With sustainability filling the gap between nanotechnology and food packaging, edible films with CDs are a revolutionary and sustainable way of preserving food, which is longer lasting, safer, and more environmentally friendly.