Zinc oxide-modified composites as a new antimicrobial coatings for application in biomedical industry – synthesis, thermal stability and antimicrobial properties

Abstract In recent years, the incidence of hospital-acquired infections has been increasing, which may be caused by the emergence of antibiotic-resistant bacteria. A solution to this problem may be the synthesis of composites containing the addition of compounds with antimicrobial properties, which can form a covering layer. They can limit the spread of bacteria and also reduce the formation of biofilm on the surface of equipment. The optimization of the polymer composition of methacrylate-based composites modified with zinc oxide was identified as the main objective of the research presented in this article. With the use of ATR/FT-IR technique, the structure and qualitative evaluation of the obtained composite materials were performed. The modified composites’ thermal resistance and decomposition process were also determined. The antimicrobial potential of the polymers against Gram-negative bacteria ( Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922) and Gram-positive bacteria ( Staphylococcus aureus ATCC 25923) was determined with a modified disk diffusion method, the serial dilution method and the method with TTC. It was observed that incorporating zinc oxide into the structure of the described polymers significantly increased the antimicrobial potential of the composites and reduced bacterial biofilm formation on their surface. In the case of the effect of composite materials on P. aeruginosa , the largest zone of growth inhibition was determined for BPA.DM + AEH + 10 %ZnO, for E. coli , the largest zone of growth inhibition was 0.6 cm for BPA.DM + NVP + 10 %ZnO, and for S. aureus it was also 0.6 cm for BPA.DM + NVP + 10 %ZnO. Notably, all the materials exhibited antibacterial activity upon contact with bacterial cells. Assessing the percentage of bacterial growth inhibition revealed that had the greatest effect on P. aeruginosa was observed with BPA.DM + MMA + 10 % ZnO (49.7 % ± 0.5 % after 12 h and 49.9 % ± 2.1 % after 24 h) and BPA.DM + NVP + 10 % ZnO (62.4 % ± 2.4 % after 12 h). The other materials with the greatest effect on E. coli were BPA.DM + AEH (46.0 ± 3.1 % after 12 h and 48.0 ± 0.9 % after 24 h), BPA.DM + AEH + 10 % ZnO (46.7 ± 2.3 % after 12 h) and BPA.DM + NVP (53.5 ± 2.2 % after 24 h). Against S. aureus , the highest percentage of growth inhibition was determined for BPA.DM + MMA (56.3 % after 24 h), BPA.DM + HEMA (48.6 % after 24 h), and BPA.DM + NVP (47.9 % after 24 h).