Photoresponsive HOF-Based Intelligent Packaging for Real-Time Monitoring Food Freshness

Real-time monitoring of food freshness is critical for public health, yet conventional packaging lacks the capability for quality feedback. While biogenic amines (BAs) are well-established indicators of food freshness assessment, most of reported sensors rely on the single "turn-off" mode that are prone to environmental interference and false positives. Herein, we developed a high-performance intelligent packaging platform featuring independent fluorescence-phosphorescence signals based on hydrogen-bonded organic framework (HOF) composites. Utilizing the host-guest assembly strategy, 4-carboxyphenylboronic acid (CPBA) was encapsulated within the melamine-cyanuric acid (MC) HOF yielding ultralong phosphorescence with a 1400 ms lifetime. By further integrating pyrene-based HOF (PFC-1), the dual-signal sensor (PFC@MCCPBA) achieves rapid and highly selective detection of BAs via the "turn-on" response mode with low limits of detection. Furthermore, a flexible intelligent packaging film was fabricated, demonstrating intuitive, real-time monitoring of food freshness. This study provides a novel strategy for designing multiresponsive HOF-based materials and advances the development of intelligent food packaging systems.