Lysozyme and Vancomycin Co-Loaded on Mesoporous Silica Nanoparticles; a “Trojan Horse” with Synergistic Antimicrobial Effects

Nanotechnology is emerging as a novel strategy to increase the susceptibility of pathogens resistant to conventional antibiotics. Another effective approach is combination therapy, where multiple therapeutic agents are used simultaneously to enhance treatment efficiency. In this study, both nanoparticles-based formulation and combinatorial therapy were employed to create an effective antibacterial system targeting infectious bacteria. Lysozyme (Lys) and Vancomycin (Van) were co-loaded onto mesoporous silica nanoparticles (MSNs), resulting in Lys-Van-MSNs. The antimicrobial activity of these nanoparticles was assessed by measuring the minimum inhibitory concentration (MIC) against Staphylococcus aureus . The MIC values for Lys-Van-MSNs were 0.85 µg/ml for Van and 0.168 mg/ml for Lys, indicating reductions of 86.4% and 93.7% respectively, compared to the free forms of Van and Lys. Furthermore, the cytotoxicity of these antimicrobial complexes was tested using MTT, ROS, and hemolysis assays on three different human cell lines: breast, fibroblast, and AGS cells, showing negligible cytotoxic effects. Given their synergistic bactericidal properties and excellent biocompatibility, the MSNs-based formulation of combined antimicrobial agents presents a straightforward and effective approach for developing robust tools to combat bacterial infections.