Novel Antimicrobial Composites Modified with Nanosilver, CuSO₄, Benzethonium Chloride, and ZnO

The antibiotic and drug resistance of various bacterial and fungal strains poses a significant challenge to medicine and industry. The subject of numerous studies is how to limit the spread of microorganisms and biofilm formation on various surfaces. This research focuses on the antibacterial and antifungal properties of cross-linked methacrylate-based composites for specific applications. These composites were modified using 10 wt.% of compounds with scientifically proven antimicrobial properties. These include nanosilver, copper sulphate, benzethonium chloride, and zinc oxide. The antimicrobial potential against the following bacteria and fungi was determined: Gram-positive bacteria (Staphylococcus aureus); Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli); and the pathogenic fungi Candida albicans and Aspergillus niger. Using the modified disc-diffusion method alongside a serial dilution method demonstrated an inhibitory effect on the viability and formation of bacterial and fungal biofilms. It was demonstrated that-in liquid cultures-composites containing benzethonium chloride inhibited the growth of P. aeruginosa by over 75%, more than 50% of E. coli and more than 70% of S. aureus. Growth inhibition of C. albicans exceeded 80% for selected composites (BPA.DM + NVP + CuSO₄, BPA.DM + NVP + ZnO), while all composites inhibited the growth of A. niger by more than 45%, and in some cases (BPA.DM + HEMA + CuSO₄, BPA.DM + HEMA + Ag, BPA.DM + MMA + Ag and BPA.DM + AEH + CuSO₄) by more than 90%. Additionally, these composites significantly reduced biofilm formation on their surfaces. Modification with zinc oxide and benzethonium chloride resulted in materials that were non-toxic to normal human skin fibroblasts. To sum up the obtained results, it can be stated that these multifunctional materials with antibacterial properties could be used in medical devices, coatings, and other specialised applications where microbial contamination is a significant issue.