Polydiacetylene-based sensors for food safety and intelligent packaging: Chromatic mechanisms and shelf-life applications

Polydiacetylenes (PDAs) are versatile chromatic materials enabling rapid, cost-effective visual detection of food contaminants, spoilage indicators, and physicochemical changes. Their conjugated backbone undergoes stimulus-responsive optical transitions for real-time sensing without instrumentation. This review provides a comprehensive synthesis of PDA-based sensors for food applications, integrating chromatic mechanisms, functionalization strategies, supramolecular architectures (vesicles, films, nanocomposites), real-matrix performance, and patent trends. Adopting a systematic approach, this integrative review compiled publications up to February 2025 across nine literature databases and two patent platforms. Empirical studies in English or Portuguese detailing PDA structure and preparation and food quality applications were included, while purely theoretical works were excluded. Critical limitations — matrix interference, long-term instability — are discussed alongside priorities for scalable, selective platforms in intelligent packaging. By bridging molecular fundamentals with packaging technologies, PDA sensors emerge as a promising technology for continuous monitoring, intelligent packaging, and food safety assurance.