Facile design of reduced graphene oxide decorated with Cu2O nanocube composite as antibiofilm active material

Abstract

Stable reduced graphene oxide nanosheets decorated with cuprous oxide nanocubes (rGO/Cu2O) composite was fabricated via a facile two-phase method. rGO with 0.5–2 nm sheet thickness was successfully prepared using a modified Hummer's approach followed by a hydrothermal reduction technique. Controlled Cu2O nanocubes with 70–90 nm average diameters and a {100} growth direction were synthesized by a wet chemical technique at room temperature without using any surfactants or templates which are usually toxic and difficult to wash. The antibacterial and antibiofilm activity of rGO/Cu2O nanocomposite was studied toward Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis. Minimum inhibitory concentration (MIC) values of rGO/Cu2O composite (5.9, 2.9, and 2.9 μg/mL for E. coli, P. aeruginosa, and B. subtilis, respectively) showed higher activities as compared to free kanamycin (MICs within 23.4–64 μg/mL) and streptomycin (MICs within 23.4–187 μg/mL). Biofilm formation and mature biofilm of the three tested microbes were significantly eradicated using MIC and higher-MIC values of the rGO/Cu2O nanocomposite, respectively. Scanning electron microscopy elucidated the antimicrobial mechanism of the nanocomposite through the complete wrapping of the bacterial cells and disrupting their shape morphology. Our findings provide a great platform for antibacterial nano-materials that could be used in water sources in the dispersion form or to be incorporated with coating materials to inhibit microbial growth and biofilms.