Development of a chitosan/polyethylene oxide/ginger nanocomposite: structural characterization and antibacterial performance

Abstract

The development of bio-based antibacterial materials using natural additives is a crucial strategy for reducing reliance on hazardous synthetic chemicals. This study investigated the effect of incorporating ginger nanoparticles (GNPs) at varying concentrations (1, 2, 3, and 4 mL) into a chitosan/polyethylene oxide (PEO) blend to enhance its antibacterial properties. XRD analysis revealed that hydrogen bonding between chitosan and PEO produced a broad peak at 23.60°. The addition of the GNPs intensified this peak and introduced a sharper feature at 19.00°, confirming the successful interaction between the nanoparticles and the polymer matrix. FTIR spectroscopy showed new C–O–C vibrational bands at 1107 cm−1 upon blending, with further spectral changes observed after GNP addition, indicating the formation or disappearance of specific functional groups. The incorporation of the GNPs was demonstrated by a new absorption peak at 235 nm, and the semi-crystalline nature of the nanocomposite was confirmed by optical analysis. TEM revealed that the GNPs had diameters of 36.6 ± 13.8 nm, while zeta potential analysis at 25 °C recorded count rates of 106.8, 71.90, and 83.50 kcps for three distinct particle bands, and the mean was −19.33 mV, with a zeta potential deviation of 14.0 mV. The value of the zeta potential indicated the moderate stability of the GNPs. SEM demonstrated that increasing the GNP concentration led to larger, aggregated particle morphologies, with complete coalescence at the highest concentration. The chitosan/PEO blend exhibited higher thermal stability than pure chitosan, while the final polymer nanocomposite showed reduced residue levels at elevated temperatures. Antibacterial testing against Gram-positive (Enterococcus and Staphylococcus aureus) and Gram-negative (Escherichia coli and Klebsiella) bacteria demonstrated that the GNP-loaded nanocomposite exhibited enhanced antimicrobial activity compared with the pure polymer blend. For Gram-negative bacteria, the activity was small or negligible. These results position the chitosan/PEO/GNP nanocomposite as a promising bio-based material for antibacterial applications.