Study Of Antibacterial Effects Of Graphene Oxide Composites On Pathogens

For the long-term and frequently use of pesticides and antibiotics, more and more superbugs with strong drug resistance appear, which severely threaten human health. Thus looking for new efficient and safe sterilization materials to substitute traditional drugs has attracted much attention during last decades. Specially, nanomaterials show great potential for mediating negligible drug resistance for bacterial and has always been widely used for sterilization. Keep all these issues in mind, we loaded silver nanoparticles and graphite like carbon nitride on graphene oxide, respectively, and studied their antibacterial effects and potential mechanism. The main content and results were presented as following:1. The GO-AgNPs nanocomposite was fabricated through the interfacial electrostatic self-assembly method. The GO-AgNPs nanocomposite with good dispersibility in water showed enhanced antimicrobial activity at an exceedingly low concentration（9.37 μg/mL） compared to the pure AgNPs（12.45 μg/mL） and GO nanosheets（250 μg/mL）, which may prevent supererogatory effect on the host plant. Results from SEM and TEM analyses indicated that the synergy of both GO sheets and AgNPs played a vital role in their inactivation effects. Results from the detached leaf experiment have confirmed that the nanocomposite can significantly control the development of the leaf spot caused by F. graminearum spore, and protect plants from pathogen infection.2. We achieved g-C₃N₄ from urea, and the GO/g-C₃N₄ composite contains with 1 wt% GO was synthesized by a simple sonochemical method. GO/g-C₃N₄ could kill 97.9% E. coli when under visible light for 2 h, in the same conditions g-C₃N₄ only have 19.8%. The experiment with scavengers revealed that the h+ was the main reason for bacterial death. The SEM images revealed that the holes distorted and even ruptured cell membrane. It was due to the GO can accept and transfer e- to improve the efficiency of electron–hole pairs separation, GO/g-C₃N₄ had superior antibacterial effect to g-C₃N₄. And the photocatalyst exhibited stable and highly photocatalytic disinfection even after four cycles.