Visible light sensitive Ag/TiO₂/graphene composite as a potential coating material for control of Campylobacter...

Infectious diarrhea caused by the food borne pathogen, Campylobacter jejuni, is a major threat to public health worldwide leads high incidence of child mortality each year. In the present study, hydrothermal synthesis of Silver-Graphene-TiO₂ nanocomposites along with TiO₂, TiO₂-Graphene and TiO₂-silver nanocomposites was done and the samples were characterized using X-ray diffraction (XRD), tunneling electron microscopy (TEM) and UV-Vis Spectroscopy. Effect of silver and graphene addition on the broad spectrum antibacterial ability of TiO₂ was studied under visible light. Moreover, the effects on bacterial survival, membrane integrity, cellular motiltiy and biofilm formation of C. jejuni were also evaluated. A synergetic effect of silver and graphene on Silver-Graphene-TiO₂ nanocomposites was observed as indicated by its increased visible light sensitivity and enhanced antibacterial activity under visible light compared to its parent derivatives. Silver-Graphene-TiO₂ composites effectively reduced growth and caused leakage of protein and DNA from C. jejuni cell. Atomic Force Microscopy was used to confirm bacterial cell damage. Besides, it also reduced motillity, hydrophobicity and autoaggregation of C. jejuni and showed excellent inhibition of biofilm formation. Furthermore, no significant cytotoxicity of synthesized nanoparticles was observed in human cell lines. We propose that Silver-Graphene-TiO₂ composites can be used as effective antimicrobial agents to control the spread of C. jejuni by preventing both bacterial growth and biofilm formation.