Interaction of Graphene Oxide with Model Bio-membrane: Insights into the Structure of the Membrane

Graphene oxide (GO) holds a similar structure of graphene with a range of oxygen functionalities such as carboxyl groups on the edges and, the hydroxyl and epoxies on the basal plane. Presence of oxygen-containing functional groups increases its water dispersity and facilitate its applications in many bio-fields including cell imaging, drug-delivery and bio-sensing. As the cellular membrane is the first target of any foreign molecule. Hence, the mechanism of interaction of GO with this membrane is very crucial to understand for extending the future applications of graphene-based materials. In present work, the x-ray reflectivity (XRR) and grazing incidence small-angle x-ray scattering (GISAXS) techniques have been used to extract the structural details of the GO-membrane complex. XRR study from lipid multilayers has shown a distinct effect of added GO on the position and shape of Bragg peaks obtained from the smectic liquid crystalline phases. GISAXS has provided the in-plane organization of the lipid molecules in the presence of GO in the membrane. The electron density profile obtained from the XRR analysis and the lattice deformation detected by the GISAXS study has provided the detailed molecular organization of the complex.