Innovative biocomposite films: Green synthesis of chitosan/collagen/maltodextrin/Moringa crosslinked with citric or tannic acid for sustainable antimicrobial agents

Investigating the potential of biocomposite materials has attracted significant interest over the past decade due to the growing demands of the pharmaceutical industry. This study focuses on the synthesis of novel films based on chitosan (Ch), collagen (Coll), and maltodextrin (MD), crosslinked with two natural agents—tannic acid (TA) and citric acid (CA)—and incorporating extracts from Moringa oleifera (Mo), a medicinal plant known for its therapeutic benefits. The originality of this research lies in the development of biocompatible, non-toxic, and interconnected films with enhanced biological functionality, fabricated entirely from natural components. The fabricated Chitosan/Collagen/Maltodextrin/Moringa (Ch/Coll/MD/Mo) biocomposite films were comprehensively characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and derivative thermogravimetry (DTG), confirming successful crosslinking. Molecular interactions and composite structure were analyzed by FTIR, revealing the presence of functional groups from all components and highlighting strong hydrogen-bonding interactions between the biopolymers and tannic acid, as well as chemical crosslinking mediated by citric acid. SEM micrographs demonstrated smooth and homogeneous surface morphologies of the films. TGA and DTG analyses elucidated the thermal degradation behavior of the films, providing insights into intermolecular interactions and their influence on thermal stability. The results demonstrated that the physicochemical and biological properties of the biocomposite films were strongly influenced by the concentration of Moringa oleifera . In vitro antibacterial assays revealed pronounced antimicrobial activity against a broad spectrum of pathogens, including three Gram-negative bacteria ( Escherichia coli, Pseudomonas aeruginosa, and Salmonella enterica ), two Gram-positive bacteria ( Staphylococcus aureus and Bacillus subtilis ), and the fungal species Candida albicans . Minimum inhibitory and bactericidal concentrations (MIC/MBC) ranged from 75 to 350 μg/mL, depending on formulation and microorganism. Notably, the Ch/Coll/MD/10%Mo–CA film, containing a higher Moringa oleifera loading (10 wt%) and crosslinked with citric acid (2 wt%), exhibited the strongest antimicrobial performance, as evidenced by its low minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values, achieving MIC values as low as 100 μg/mL and complete microbial eradication within 60–105 min, as confirmed by time-kill kinetics. Furthermore, time-dependent antimicrobial evaluations demonstrated that this formulation achieved the fastest microbial inactivation across all tested strains. Overall, the engineered biocomposite films with integrated microbial barrier functionality demonstrate significant promise for non-load-bearing biomedical applications, offering effective and practical solutions aligned with principles of environmental stewardship.