Novel nanoblades of graphene oxide decorated with zinc oxide nanocomposite as a powerful anti-microbial active weapon

Abstract

Graphene-based materials have emerged as new green broad-spectrum antibacterial agents with low bacterial resistance and sustained release properties. In the current work, a novel graphene-ZnO hybrid nanocomposite was prepared as an effective antibacterial weapon with a blade-like structure. Graphene oxide nanosheets decorated with ZnO nanospheres (GO/ZnO) were facilely prepared and controlled via a one-phase method. Nano-GO with 2 nm-thick sheets was prepared via a modified Hummers' procedure. A wet-chemical process was used to produce controlled 60 nm-ZnO nanospheres. Analytical methods such as field emission TEM and SEM microscopes were used to characterize the produced nanocomposites. Several gram-positive and gram-negative bacteria were used to test the anti-microbial activity of the developed materials. Through the microdilution method, GO/ZnO composites showed outstanding antibacterial activity with minimum inhibitory concentrations of 20 µg/mL for S. aureus, Bacillus subtilis, B. pertussis, as well as 40 µg/mL for H. pylori and P. aeruginosa. GO/ZnO nanocomposite’s bacterial resistance was mediated via nanoblade-edges, cellular rupture, and generation of reactive oxygen species. We concluded that a considerable quantity of oxidative stress created on the composite surface was involved in the bactericidal pathway and was responsible for eradicating the mature biofilm. ZnO NPs' dispersion in an aqueous solution was boosted by GO nanosheets, which also prevented aggregation and enhanced the anti-microbial performance.