Synthesis Of Graphene Quantum Dot-silver Nanoparticle And Its Antimicrobial Activity Against Microganism

Infectious diseases caused by pathogenic bacteria not only hindered the growth of crop and animal, resulting in the reduction of crop yields as well as death of livestock, but also threatened human health and property. There are serious challenges facing traditional antibacterial drugs in the area of disease prevention and diagnosis as the breeding of drugresistance bacteria. It is urgent to explore new root to restrain bacterial growth, to prevent the outbreak of infectious disease and to protect the health of human. Nanomaterials have attached attention of scientist for their broad-spectrum antibacterial ability and high antibacterial effect. In this article, we synthesized graphene quantum dot-silver nanoparticle(GQD-Ag) and researched on its antibacterial ability. The main works and results are as follows:We synthesized graphene oxide(GO) through Hummers method; using GO, hydrogen peroxide and ammonium hydroxide as raw materials, synthesized graphene quantum dot(GQD) under mild condition; using GQD and Tollens’ reagent as raw materials, synthesized graphene quantum dot-silver(GQD-Ag) nanoparticle through in-situ reduction. Fluorescence spectra show that, GQD was of great fluorescence intensity as well as antiphoto-bleaching property, the emission spectra of GQD shifted red as the excitation wavelength increased; Fourier transform infrared spectra show that, both of GO and GQD were rich of oxygen-containing functional groups which lay the foundation of further modification; transmission electron microscope images show that, size of GO, GQD and GQD-Ag were 1 μm-2 μm, 10 nm and 30 nm; dynamic light scattering spectra show that, both of GO, GQD and GQD-Ag were well dispersed with narrow size distribution.We analysed the property of GQD-Ag. Results suggested that GQD-Ag could catalyze the decomposition of hydrogen peroxide and generate hydroxyl radical and that GQD-Ag was of better reducibility than GQD. We tested the antimicrobial activity of GQD-Ag towards Escherichia coli(E.coli) and Fusarium graminearum(F. graminearum), explored the antibacterial mechanism of GQD-Ag. Results revealed that growth of E. coli and germinate of spores of F. graminearum had been restrained in presence of GQD-Ag, implied the antimicrobial effect of GQD-Ag towards both bacteria and fungus. The lowest antimicrobial concentration of GQD-Ag was lower than 10 μg/m L.