Multifunctional bagasse nanocellulose-based composite films for intelligent packaging and physiology signal monitoring

Metabolism, transpiration, and invasion of pathogens during the storage and transportation of fruits can lead to significant waste and even food safety issues. Therefore, real-time, rapid, and accurate non-destructive monitoring of physiological information during the storage of fruits and vegetables to assess fruit freshness is crucial. Herein, we engineered a degradable and multifunctional humidity sensing film for monitoring fruit freshness. The film is fabricated through the co-assembly of bagasse cellulose nanocrystals (CNC), okra polysaccharides (OPs), silver nanowires (Ag NWs), and phytic acid (PA), utilizing dynamic hydrogen and phosphate bonds. This innovative design endows the CNC/OPs/PA/Ag NWs (COPA) composite film with outstanding mechanical properties, water resistance, low water vapor permeability, antibacterial, degradability, and moisture-sensing ability. Notably, the proposed COPA humidity sensor exhibits high linearity (R² = 0.994), ultralow hysteresis (1.24%), and 32 days of operational stability across a 35%–98% relative humidity (RH) range, enabling precise freshness monitoring during fruit storage. Significantly, the COPA film prolonged the shelf-life of packaged fruit when compared to conventional PE film packaging. This research establishes a foundational framework for next-generation smart sensors in food quality management and biomedical monitoring applications.