Antibacterial Composites Based on Alginate/Egg White and ZnO Nanoparticles with the Addition of Essential Oils

A series of hydrogels containing sodium alginate at different concentrations (2%, 3%, and 4%) and egg white were prepared through ionic cross-linking with calcium chloride (CaCl₂) to obtain composite dressing materials. ZnO nanoparticles coated with eucalyptus or lavender essential oil were introduced into the hydrogel matrix to enhance antibacterial properties. The resulting hydrogels were freeze-dried to enhance mechanical properties, increase the porosity of the dressing, and facilitate further evaluations. A variety of analytical methods, including scanning electron microscopy (SEM), X-ray dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the composites. The developed composites exhibited high porosity and a swelling degree exceeding 200% after 3 days. Additionally, water absorption capacity increased with higher alginate concentrations in the samples. Furthermore, they demonstrated significant antibiofilm activity against Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli, with the samples containing 4% alginate showing the best results.