Antimicrobial activities of polyethylene glycol and citric acid coated graphene oxide-NPs synthesized via Hummer’s method

Abstract

Graphene oxide (GO)-NPs possess excellent physicochemical and biological properties and could have prominent antimicrobial activities. We used solution-based Hummer’s method to synthesize pure, CA coated and PEG coated GO-NPs and the XRD revealed hexagonal lattice structure and the crystallite size of pure and coated GO-NPs calculated in the range of 7–16 nm. In addition, a spongy like surface in pure GO-NPs and randomly crumpled like surface by using the CA and PEG coating agents was also identified and SEM images irregular, non-uniform and rod shape morphology of the graphite powder. The GO in the UV region and the band gap decreased from 2.30 to 2.03 eV while different modes (CC and CO) on the surface of pure and coated GO-NPs were evident as indicated by Raman spectra. Finally, in-vitro antimicrobial activity was assessed against two-gram negative bacterial strains viz. A. hydrophilaand E. coli and one fungal stain F. avenaceum at 10 and 20 mg/mL concentrations. Our results indicated enhancement in the inhibition zones of pure GO-NPs from 8 to 17 mm, PEG coated GO-NPs from 8 to 20 mm and CA coated GO-NPs from 8 to 17 mm respectively. Overall the PEG coated GO-NPs had prominent antimicrobial activities and we recommend application of polymer coated GO-NPs for wound healing process.

Keywords

• PEG
• Graphene oxide (GO)
• Antimicrobial
• A. hydrophila
• E. coli
• F. avenaceum