Mesoporous CuS/SiO2 as a sulfamethoxazole loading carrier against Escherichia coli and Staphylococcus aureus

Abstract

Metallic nanoparticles (NPs) (Ag, Cu, CuO and CuS) have antibacterial properties that are closely related to the size and morphology that enable a large surface-to-volume ratio. In solution, metallic NPs are likely to be agglomerated or precipitated, thus decreasing their biocidal activity. The surface functionalization of copper sulfide NPs on mesoporous SiO2 spheres (PMSi) was successfully achieved and characterized by XRD, SEM, TEM, UV–vis and nitrogen physisorption. Since the incidence of allergies in humans caused by sulfamethoxazole (SMX), a water insoluble bacteriostatic antibiotic (commonly used in combination with trimethoprim), has been detected to be increasing, in this research work, it was decided to study the antibacterial activity of PMSi loaded with SMX against Escherichia coli and Staphylococcus aureus, Gram-negative and Gram-positive bacteria, respectively. The antibacterial synergistic performance displayed by loading SMX on CuSNPs was studied by the minimum inhibitory concentration (MIC) method. The ANOVA analysis with Dunnett's multiple comparison tests showed a statistically significant difference between the CONTROL and PMSi composites unloaded and loaded with SMX on E. coli and S. aureus. CuS and Cu functionalized on PMSi exhibited a good spectrum of antimicrobial activity against Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria, in contrast with the current literature.