Preparation And Structure-properties Of Functionalized Reduced Graphene Oxide Based Silver Nanoparticles Composite Antibacterial Materials

With the excellent characteristics of safety and nontoxicity, high-efficiency,broad-spectrum, and long-term antibacterial activity, silver nanoparticles (AgNP) hasbeen applied in the field of medical care, eco-environment, architecture, kitchen andtoilet, electronics, and daily products, etc. However, shortcomings like its high price,difficulty in dispersion, and the tendency to be oxidized and discoloration are stillrestrictions for its wider range of applications. Graphene is a single-atom-thicktwo-dimensional graphitic carbon material. Many superior properties of it, such ashigh specific surface area, excellent thermal conductivity and extraordinarymechanical and electron transportation properties, etc. make graphene to be a perfectsubstrate for functional materials. Therefore, in this thesis, we used water-solubleorganic compounds to modify reduction graphene oxide (rGO) to obtain thewater-soluble rGO substrate, and then we loaded AgNP on it to prepare anrGO-AgNP composite antibacterial material. Structures and preparation processes areinvestigated and properties are characterized in this thesis.First, we prepared silver nanoparticles/polyethyleneimine (PEI)-reductiongraphene oxide (AgNP/PEI-rGO) composite antibacterial material which is modifiedby polyethyleneimine. XRD, FTIR, XPS, TEM, AFM, Zeta-potential, ICP andUV-VIS are used to characterize the properties of the material, and the antibacterialactivity, cell toxicity and biocompatibility are also analyzed. Results show that PEIhas been attached to the rGO throgh O=C-NH, and the thickness of rGO modified byPEI was0.6nm. In addition, AgNP have been loaded on the functionalized rGOuniformly with the diameter distributed in5-15nm, and the Zeta-potential is-46.7mV.Compared with the release rate of AgNP modified by polyvinylpyrrolidone(PVP) was90.7%, the release rate of AgNP in AgNP/PEI-rGO was slower, and just was72.5%,in ultrapure water after20days. After being stored in dark or nature light level for7days, PVP/AgNP aggregated significantly, but AgNP/PEI-rGO did not changedistinctively. Compared with PVP/AgNP, AgNP/PEI-rGO has the higher antibacterialactivity and biocompatibility, lower biological toxicity. And then, we prepared sodium naphthalene sulfonate(NA)/reduction grapheneoxide-Silver nanoparticles (AgNP/NA-rGO) composite antibacterial material which ismodified by1-sodium naphthalene sulfonate. XRD, XPS, TEM, AFM, Zeta-potential,ICP, UV-VIS and fluorescence spetra are used to characterize the properties of thematerial, and the antibacterial activity, cell toxicity and biocompatibility are alsoanalyzed. Results show that content of AgNP in the composite material is3.6%,solubility in the water could reach1.1mg/mL, and the Zeta-potential is-42.3mV. Inaddition, the suspension formed by this material could keep stable in the aqueouussolution for more than3months without deposition. Compared withpolyvinylpyrrolidone(PVP), NA-rGO could prevent Ag particles from oxidationeffectively, which leads to a better sustained-release effect; The antibacterial ratecould reach92.4%and96.9%after contacting with E. coli and S. aureus respectivelyfor6h; This composite nano-material is proved to have a good biocompatibility andjust slight cell toxicity.