Antibacterial Activity of Reduced Graphene Oxide

Abstract

The increasing biological use of graphene-based materials has prompted research inquiries on their effects on microorganisms. The work herein reported different types of microbiological activity of reduced graphene oxide (RGO). At relatively high concentrations (200 and 400 μg/mL), RGO exhibited antibacterial activity on the model bacterium Escherichia coli, while at lower concentrations (10 and 50 μg/mL), interestingly, no antibacterial effect was observed. Instead, an increase in the viable population after exposure at lower concentrations was observed, verified by colony counting and fluorescence microscopy. Further investigation ruled out the possibility of nutrient release from RGO being responsible for this growth-enhancing effect, whereby a comparable number of viable cells were found in the particle-free RGO leachate systems relative to the control. A before and after exposure X-ray photoelectron spectroscopy (XPS) analysis of the RGO detected less presence of C-C bond on the particle surface, suggesting the ability of the bacterium for the use of the carbon-based materials for growth. This potential RGO-cell interaction is further supported by the observed emergence of C-N bond on the particle surface, the nitrogen moieties most likely of bacterial (cell envelope) origins. Although still an early evidence, such RGO-cell interactions could explain the viable cell increase observed at the lower concentration RGO systems. The present study highlights the concentration-dependent microbiological effects of RGO, clarifying the contradicting reports on the growth enhancing versus antibacterial effect of graphene-based materials. The knowledge is important not only for the antibacterial formulation of carbon-based materials but also when assessing their environmental impact.

Antimicrobial, anticancer, and biofilm inhibition studies of highly reduced graphene oxide (HRG): In vitro and in silico analysis

“…Gram-positive strains MRSA, S. aureus , and B. subtilis showed susceptibility to HRG with a zone of inhibition of (28.7 ± 2.21, 24.31 ± 1.98 & 24.12 ± 1.17) in comparison to ampicillin with a zone of inhibition of (21.0 ± 2.27, 19.21 ± 1.82 & 18.86 ± 1.21), respectively ( p ≤ 0.05). A previous study found that E. coli showed resistance to reduced graph oxide nanoparticles, although it was susceptible to a high concentration of these nanoparticles ( Mann et al, 2021 ). Graphene and its derivatives also show a valuable impact in tissue engineering and exhibit strict antimicrobial activities.…”

“…27, 19.21 ± 1.82 & 18.86 ± 1.21), respectively (p ≤ 0.05). A previous study found that E. coli showed resistance to reduced graph oxide nanoparticles, although it was susceptible to a high concentration of these nanoparticles (Mann et al, 2021). Graphene and its derivatives also show a valuable impact in tissue engineering and exhibit strict antimicrobial activities.…”

Improving the Durability of Chitosan Films through Incorporation of Magnesium, Tungsten, and Graphene Oxides for Biomedical Applications

“…The antibacterial activity of the scaffold against E. coli plateaued while it exhibited a decrease in the behavior against S. aureus reaching 8.5±0.5 mm. This could be because at lower doses (10 and 50 g/mL), GO has been demonstrated to have no antibacterial action against E. coli bacteria [57] . However, GO demonstrated antibacterial action against E. coli bacteria at greater doses (200 and 400 g/mL) [57] .…”

“…This could be because at lower doses (10 and 50 g/mL), GO has been demonstrated to have no antibacterial action against E. coli bacteria [57] . However, GO demonstrated antibacterial action against E. coli bacteria at greater doses (200 and 400 g/mL) [57] . It is yet unknown how GO works against bacteria [58] .…”

Cationic and Anionic Substitutions in the Antibacterial and Biocompatibility Properties of Sol-Gel Derived Hydroxyapatite Nanocomposites

“…Zn-HAp and Ti-HAp are more effective against each of the four bacteria, but HAp-rGO is more effective at greater doses. [68,69]. This might treat post-workplace injury disorders and bone joint infections at an early stage without identifying the major driver of the relevant microbe, allowing for a number of advancements in current clinical medicine [66,70].…”