Characterization of Polysaccharide-Based Composites Enriched with Zinc Oxide and Bacitracin for the Treatment of Infected Wounds

This study aimed to manufacture and characterize highly porous dressings based on gellan gum (GG) and sodium alginate (Alg) hydrogels modified with zinc oxide (ZnO) and bacitracin (BAC) intended for infected and exuding wounds. ZnO nanoparticles (ZnO(n)) were 26 ± 4 nm in size according to atomic force microscopy (AFM), while the size of the microparticles (ZnO(m)) was 1.02 ± 0.01 µm according to laser diffraction measurements. Their relative surface areas were 39.16 m2/g and 4.56 m2/g, respectively. Microbiological studies showed that ZnO(n) exhibited antibacterial activity in contact with the Gram+ Staphylococcus aureus; thus, they were selected for embedding in a hydrogel matrix. Four types of composite hydrogel samples were manufactured: GG/Alg, GG/Alg+ZnO, GG/Alg+BAC, and GG/Alg+ZnO+BAC, which were subjected to freeze drying. The water absorption of all materials exceeded 4000%, showing excellent liquid absorbability. Burst release of BAC was found at a level of 90% in the first 2 h. In vitro cytotoxicity studies on L929 fibroblasts did not show a toxic effect of extracts from the GG/Alg and GG/Alg+BAC samples, contrary to samples supplemented with ZnO(n). In microbiological studies, the enhanced antibacterial effect of ZnO(n) and BAC was observed in contact with Staphylococcus aureus and Staphylococcus epidermidis strains. Therefore, GG/Alg+BAC+ZnO is the most promising dressing system for the treatment of infected and exuding wounds.