Antimicrobial activity of graphite oxide doped with silver against Bacillus subtilis, Candida albicans, Escherichia coli, and Staphylococcus aureus by agar well diffusion test: Synthesis and characterization

https://doi.org/10.1016/j.msec.2021.111934Get rights and content

Highlights

  • The amount of silver changed the microstructure and functional groups of graphite oxide

  • Low silver concentration exhibited a high dispersion of metal ions along the graphite oxide surface

  • GrO-0.5Ag material presented the same non-lattice and lattice oxygen amount

  • Electron mobility, synergy between functional groups and silver carbonate formation enhanced the antimicrobial activity

  • GrO-0.5Ag showed a high percentage of inhibition effect in the following order: S. aureus > B. subtilis > E. coli > C. albicans

Abstract

In the present study, graphite oxide, graphite oxide doped with 0.8 g AgNO3 named GrO-0.5Ag, and graphite oxide doped with 1.25 g AgNO3 named GrO-1.0Ag (silver-doped graphitic materials) were synthesized by the modified Hummers and chemical doping methods. Subsequently, its antimicrobial activity against Bacillus subtilis, Candida albicans, Escherichia coli, and Staphylococcus aureus microorganisms was evaluated by agar well diffusion test with 1 and 2 mg·ml−1 of material concentrations. The silver-doped graphitic materials were characterized by X-Ray Diffraction, Fourier-Transform Infrared, Raman, X-Ray Photoelectron spectroscopies, and Scanning Electron Microscopy. The GrO-0.5Ag material showed a percentage of inhibition effect of 86, 82, 48, and 45% with respect to the positive control for Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Candida albicans microorganisms, respectively. Otherwise, the GrO-1.0Ag material showed a percentage of inhibition effect of 54% with respect to the positive control for Bacillus subtilis and less than 50% for the other microorganisms. The material concentrations showed a slight change in the percentage of inhibition effect for all microorganisms. Graphite oxide functional groups, small crystal size, free silver ions, and silver carbonate formation in silver-doped graphitic materials presented a viable alternative to inhibit bacterial growth.

Keywords

Antimicrobial activity
Silver-doped graphitic material
Bacillus subtilis
Candida albicans
Escherichia coli
Staphylococcus aureus

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