Novel colored hydroxypropyl methyl cellulose/ magnetite carbon dots films for beef packaging with DFT calculations and molecular docking study

This study investigates the preparation and characterization of a novel HPMC-MCDs (Hydroxypropyl methylcellulose-magnetite carbon dots) composite film for potential applications in food safety monitoring. While carbon dots (CDs) offer promising sensing capabilities, their inherent lack of color limits direct visual detection, a limitation addressed in this work by incorporating magnetite (Fe₃O₄) to create a visually discernible sensor. Characterization techniques, including XRD, FTIR, and SEM, confirmed the successful integration of MCDs within the HPMC matrix. The incorporation of MCDs significantly reduced the film's surface roughness. The HPMC-MCDs composite exhibited a remarkably smooth surface. DFT calculations revealed enhanced stability of the HPMC-MCDs composite. Fluorescence studies demonstrated color change in the HPMC-MCDs upon interaction with Salmonella enterica and B. cereus, suggesting potential for bacterial detection. Furthermore, the HPMC-MCDs film exhibited pH-sensitive behavior, changing color in response to pH variations, making it a promising candidate for visual monitoring of beef meat spoilage. These findings suggest that HPMC-MCDs have the potential to serve as a multifunctional sensing platform for food safety applications.