Novel electrochemical biosensors based on a biomimetic graphene-lipid bilayer interface

In our work we investigate the development of a novel electrochemical biosensor that integrates a graphene layer as the transducer element for the analysis of electroactive membrane proteins. Graphene is used as transducer because of its unique properties (high surface area, electrical conductivity, ultra-high electron mobility, wide electrochemical potential window, low charge-transfer resistance, reduction of overvoltage), all of which are responsible for the enhancement of the direct electron transfer between graphene and the membrane proteins. However, in biosensors for membrane proteins a major problem is the denaturation of such proteins when they are in contact with the electrode solid surface. To avoid this, membrane proteins are normally embedded in a biological system mimicking their native environment, the supported lipid bilayer (SLB). This study is focused on the synthesis of the graphene interface through chemical vapour deposition, on its surface treatments through a mild oxidation to improve its biocompatibility, and on the investigation of the graphene interface with SLBs. The obtained films of graphene are characterized using scanning electron microscopy, Raman spectroscopy and measuring the water contact angles before and after surface treatments. The interaction of the graphene surface with liposomes and the formation of the graphene-supported lipid bilayer are investigated using electrochemical impedance spectroscopy.