▎ 摘　　要

It is well known that graphene oxide (GO) possesses antibacterial properties towards both Gram-positive and Gram-negative bacteria. As a result, it has recently attracted a lot of interest as an active component towards pathogen inhibition. The aim of this paper is to prepare graphene oxide sheets, with two differ-ent oxygen concentrations of 15% and 39%, characterize them, and then investigate in vitro their antimi-crobial efficacy in both Gram-positive and Gram-negative bacteria. In particular, GO sheets are synthesized via the Hummer's method and subsequently, electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy are used to investigate the GO sheet morphology and structure, while Energy Dispersive X-ray Spectroscopy (EDS) is employed for elemental analysis. Subsequently, clinical isolates of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa are incubated with different concentrations of GO sheets, ranging from 0.25 mg/ml to 1.5 mg/ml for 24 h at 37 degrees C to evaluate the antimicrobial effect. The results confirmed that that Gram positive bacteria are more sensitive to GO, while GO with a higher oxygen content exhibits increased antibacterial activity. (c) 2022 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).