Glucose-mediated green synthesis of GO-Ag nanoconjugate: Enhanced antibacterial activity and water disinfection application

This study reports the green synthesis of a graphene oxide-silver nanoconjugate using glucose as a reducing agent, with its antibacterial activity tested against Escherichia coli and Bacillus subtilis. The antibacterial activity was determined by plate spreading, well diffusion and turbidity tests. The plate spreading test showed the GO-Ag nanoconjugate inhibited bacterial growth by up to 99 ± 0.50%. The results from the well diffusion test showed inhibition zones of 28.30 ± 1.50 mm and 30.20 ± 1.70 mm for E. coli and B. subtilis, respectively, compared to inhibition zones of 36.66 ± 1.70 mm and 38.30 ± 2.50 mm for ciprofloxacin. The turbidity test also showed good antibacterial activity, with a reduction in bacterial growth of 73 ± 2.46% and 76 ± 1.38% for E. coli and B. subtilis, respectively, after 4 h in the presence of 25 mg GO-Ag nanoconjugate. The GO-Ag nanoconjugate inhibited bacterial growth to less than 5 ± 1.37% for both strains in the wastewater treatment test after 48 h in the presence of the GO-Ag nanoconjugate. This study showed the GO-Ag nanoconjugate to have good antibacterial activity with potential use in water disinfection.