Fabrication of charge reversible graphene oxide-based nanocomposite with multiple antibacterial modes and magnetic recyclability.

In this work, N-alkylated poly (4-vinylpyridine) (NPVP), a cationic polymer, was firstly applied for the surface modification of Fe3O4 nanoparticles. Then the modified Fe3O4 nanoparticles (Fe3O4@NPVP NPs) combined with graphene oxide (GO) through simple electrostatic binding. Subsequently, deposited Ag nanoparticles (Ag NPs) procedure was carried out to form the multiple antibacterial nanocomposites (GO-Fe3O4@NPVP-Ag). The synthesized nanostructures were well characterized by Transmission Electron Microscope (TEM), X-ray powder diffraction (XRD), Fourier-transform infrared (FT-IR) and Raman spectroscopy. The zeta potentialmeasurement showed that the novel antibacterial nanocomposites exhibited a capacity of reversing its surface charge from negative (physiological pH) to positive (acidic condition). Furthermore, the incorporation of magnetic Fe3O4 NPs into the nanosystems facilitates the cyclic utilization of GO-Fe3O4@NPVP-Ag by magnetic separation. The antibacterial properties of GO-Fe3O4@NPVP-Ag nanocomposites were evaluated with Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Moreover, the cytotoxicity of GO-Fe3O4@NPVP-Ag nanocomposites was studied using NIH-3T3 cells. The results showed that the GO-Fe3O4@NPVP-Ag nanocomposites exhibited excellent antibacterial properties and low cytotoxicity, thus confirming its application as a promising rapid bactericide in various antibacterial fields.