COMPARATIVE EVALUATION OF ANTIMICROBIAL EFFICACY OF GRAPHENE OXIDE AND REDUCED GRAPHENE OXIDE NANOPARTICLES AGAINST COMMON ORAL PATHOGENS:IN VITRO STUDY

Background: The escalating threat of antimicrobial resistance (AMR) has driven the search for alternative
antibacterial agents. Graphene-based nanomaterials, particularly graphene oxide (GO) and reduced graphene oxide
(rGO), have emerged as promising candidates due to their unique physicochemical properties and potential
antimicrobial mechanisms.
Objective: This study aims to evaluate and compare the antimicrobial efficacy of GO and rGO nanoparticles against
common oral pathogens—Streptococcus mutans, Enterococcus faecalis, and Candida albicans.
Materials and Methods: The antimicrobial activity of GO and rGO was assessed via agar well diffusion and timekill kinetics. GO and rGO were tested at concentrations of 25, 50, and 100 µg/mL, with standard antibiotics as
controls. Inhibition zones were measured, and statistical significance was evaluated using one-way ANOVA and
Tukey’s post hoc test.
Results: GO demonstrated superior, dose-dependent antimicrobial activity compared to reduced GO, particularly
against Candida albicans (18.48 ± 0.06 mm at 100 µg/mL), followed by S. mutans and E. faecalis. rGO showed
limited efficacy in inhibition zone assays, although time-kill kinetics revealed its bactericidal potential, especially
against E. faecalis.
Conclusion: GO exhibited stronger antimicrobial performance than rGO, likely due to its higher oxygen content
and associated reactive oxygen species (ROS) generation. While rGO was less effective in static assays, its
performance in time-kill kinetics suggests potential in dynamic or prolonged-contact applications. Graphene-based
nanomaterials show promise for dental antimicrobial use, but require further optimization and in vivo validation.