▎ 摘　　要

Nanocomposite has multiple mechanisms of antibacterial action against pathogenic bacterial strains. In the present study, the highly antibacterial nanocomposite graphene oxide, chitosan and silver nanoparticles (GO-CSAg) were synthesized. The GO nanosheets were synthesized using Hummer method and Ag-NP were successfully prepared by green tea leaves extract. Subsequently, the resultant GO-CS-Ag nanocomposite was prepared by agitation process. The stability and structure of GO-CS-Ag was analyzed by UV-vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) fourier transmission spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDX), which revealed that Ag-NP and CS were uniformly deposited on GO nanosheets. The antibacterial activity of prepared GO, GO-CS, GO-Ag and GO-CS-Ag was studied against gram-positive S. aureus and S. mutans and gram-negative bacterial strains E. coll., K. pneumoniae, P. aeruginosa and S. typhi by determining the zone of inhibition using oxford cup method. The minimum inhibitory concentration (MIC) of each nanomaterial was evaluated using dilution broth method. The nanomaterials showed excellent antibacterial activity and effectively inhibit the growth of pathogenic bacterial strains. However, the antibacterial activity was in the following orders GO-CS-Ag > GO-Ag > GO-CS > GO. This outcome suggested that GO-CS-Ag nanocomposite can be potentially applied in biomaterials, biomedical and as well as in food industry.