Title : Covalent crosslinking of cellulose-chitosan biopolymers via aldehyde linkers: Synthesis, characterization, and enhanced antibacterial functionality
Abstract:
The increasing threat of antibiotic-resistant pathogens and the need for environmentally sustainable materials have accelerated research into biopolymer-based antimicrobial agents. This study addresses the question: Can natural polymers from agricultural and marine waste be engineered into potent, eco-friendly antibacterial materials through chemical modification? To explore this, we synthesized cellulose-chitosan biopolymer beads using cellulose derived from chemically treated maize corn cobs and commercial shrimp chitosan. Covalent crosslinking was achieved via Schiff base reactions using glutaraldehyde and formaldehyde as aldehyde linkers. The resulting gel beads were structurally and chemically characterized using SEM, FTIR, XRD, UV-Vis, and EDS techniques. Surface morphology analysis revealed that aldehyde crosslinking introduced globular, densely packed structures with increased amorphicity and enhanced crystallinity, especially in formaldehyde-linked composites.Spectroscopic analysis confirmed successful crosslink formation, with shifts in key vibrational bands indicating new covalent interactions between cellulose and chitosan. Antibacterial assays against Staphylococcus aureus and Pseudomonas aeruginosa demonstrated significantly enhanced activity of the crosslinked gels, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values as low as 9.37 mg/mL and 18.75 mg/mL, respectively, far outperforming untreated or uncrosslinked controls. These findings suggest that covalent aldehyde crosslinking not only improves structural stability but also dramatically boosts the antimicrobial efficacy of cellulose-chitosan biopolymers. Academically, the study expands the toolbox of natural polymer modification strategies and offers spectroscopic insights into Schiff base chemistry. Socially and environmentally, it promotes the valorization of agricultural and marine waste into sustainable biomedical materials. Such materials could be applied in wound dressings, medical devices, or antimicrobial coatings, aligning with circular economy principles and public health goals.
Keywords: Cellulose-Chitosan Biopolymer, Aldehyde Crosslinking, Antibacterial Activity, Maize Corn Cob Waste, Schiff Base Reaction
