Enhanced fluorescent multifunctional red-emitting CDs@Pr-MOF nanocomposite-embedded reinforcing electrospun films for monitoring packaged fruit freshness

Fluorescent carbon dots (CDs)-based stimuli-responsive materials exhibited considerable promise for real-time monitoring of food quality and safety, but their poor stability and reliance on single-color changes have limited their broader application. Herein, red-emitting CDs (R-CDs) were immobilized onto Pr-based metal-organic framework (Pr-MOF) through electrostatic interactions. The Pr-MOF served as an adsorption scaffold for R-CDs while also contributing to the enhanced fluorescence responsiveness of the composite. Afterward, the R-CDs@Pr-MOF nanomaterial was incorporated into a blended matrix of polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) to fabricate spinning film responsive to sulfur-based gases. The incorporation of R-CDs@Pr-MOF into the PVDF/PVP matrix moderately improved the water resistance while enhancing the mechanical properties and thermal stability of the film. Importantly, the film exhibits a clear multicolor evolution in response to analyte, effectively overcoming the single-color limitation. The MOF effectively also mitigates the comprehensive performance deficiencies of R-CDs in the packaging film. Finally, a linear correlation equation between the S RGB -value of the MOFs-based film and the quality parameters of packaged durian was established using a self-developed APP (Optimal group equation: y = (0.101 ± 0.002) x + (32.365 ± 0.753); R 2 = 0.9924; LOD: 0.086–0.836; RSD: 1.91%). Hence, utilizing digital sensing platform in conjunction with dual-channel light response mode, a powerful approach for the rapid assessment of multiple quality parameters of packaged fruits was developed. Moreover, the R-CDs@Pr-MOF material facilitates accurate and non-invasive monitoring of fruit freshness, enhancing the precision and safety of intelligent packaging systems.