Surface morphology-dependent spontaneous bacterial behaviors on graphene oxide membranes

The need for biofouling control in membrane-based water treatment has prompted the use of novel materials for membrane fabrication. Recently, engineered graphene oxide (GO) membranes produced by layer-by-layer stacking of GO nanosheets have been considered to be an economical and easy fabrication method with potential for biofouling control. However, contradictory evidence exists on the interaction between graphene-based surfaces and microorganisms in the literature. To clarify to some extent these discrepancies, the role of GO layer morphology in microbial behaviors on membrane surfaces was investigated by using Pseudomonas aeruginosa PAO1 as a model bacterium. As a result, we found a strong adhesion of P. aeruginosa PAO1 on GO membranes at an elevated GO thickness (> 1.71429 mg/cm(2)). This behavior is attributed to changes in the surface morphology, which helps harbor and trap bacterial cells. Our results reveal the significance of GO layer morphology in bacterial behaviors on membrane surfaces. Those findings suggests that GO layers with considerable roughness and curvature may serve as an absorbent for bacterial cells and potentially reduce biofouling in membrane-based water and wastewater treatment systems when used in the pre-treatment unit.