Synthesis and Characterization of Biogenic Reduced Graphene Oxide Nanoparticles with Antibacterial Properties Using Aegle marmelos

Graphene oxide nanoparticles (GO NPs) have emerged as a revolution in medicine, environment, and even agriculture
to an extent. Recently, a greener alternative, using an aqueous leaf extract from Aegle marmelos was found to synthesize
reduced graphene oxide nanoparticles and characterized using UV–Visible spectroscopy (UV–Vis), Fourier Transform
Infra-Red Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and X-Ray Diffraction (XRD) techniques. UV–Vis
analysis confirms the successful formation of GO with the characteristic peaks at the region of 235–245 nm corresponds
to π→ π* and n → π* transitions, while the similar pattern with reduced intensity was observed for rGO NPs, which indicates
the effective reduction has been taken place. Functional groups were studied using FTIR analysis. The crystalline
nature and particle size was determined using XRD analysis and the results shows the broad peak shift of GO at ~ 8° to
sharp peak in rGO NPs with the improved crystallinity and particle size of 23 nm. SEM analysis displays the crumpled,
layered sheets like structure in GO, while rGO NPs exhibit rod-like structures with well defined edges. Antibacterial
activity test was conducted for both Aegle marmelos leaves extract and Aegle marmelos leaves extract mediated rGO NPs
against common pathogens and the results shows the highest inhibition rate for Escherichia coli, followed by Staphylococcus
aureus and Bacillus subtilis. This enhanced anti-microbial activity was due to the synergic effect of the reduced
graphene oxide structure and bioactive compounds of the Aegle marmelos leaves extract. The antibacterial effect was
complemented by the membrane stress, which was produced by differentiation of the geometrical potential, because of
the rod-like rGO nanostructures. It can be utilized for the various biomedical fields such as antimicrobial coatings, wound
dressings, drug delivery systems, and biosensors.