Synthesis of ZnO nanoparticles-decorated spindle-shaped graphene oxide for application in synergistic antibacterial activity

A novel spindle-shaped graphene oxide (GO) was performed by the self-assembly of graphene oxide in the DMF. Loading uniform ZnO nanoparticles on spindle-shaped GO is used to study antibacterial property. In the ZnO/GO composites, spindle-shaped GO possessed special structure that was crumpled together with a length of ~1.0 μm and a mean diameter of 100 nm, and spherical ZnO particles with a diameter of 50 nm were fully characterized by field-emission scanning electron microscope (FE-SEM), a high-resolution transmission electron microscope (HR-TEM) and X-ray diffraction (XRD). Due to the antibacterial advantages of ZnO and GO, the mechanism underlying the interaction between composites and bacteria is elucidated in this work. The results showed that the composites could prevent bacterial proliferation and could destroy bacterial integrated membrane by the release of Zn2+ and generation of abundant reactive oxygen species (ROS). The typical gram-negative (Escherichia coli and Salmonella typhimurium) and gram-positive (Bacillus subtilis and Enterococcus faecalis) bacteria were used to investigate the significant antibacterial activity of ZnO/GO composites. The minimum inhibit concentration (MIC) value of ZnO/GO composites for the gram-positive bacteria was 31.25 ± 0.25 μg/mL, however, that for the gram-negative bacteria was 15.625 ± 0.5 μg/mL. Based on our study, this new structure composites with good antibacterial activity is regarded as a promising material for application in the medical field.