Synthesis of smooth graphene surfaces by CVD for electrochemical biosensors with supported lipid membranes

In this work we perform an ab initio study on the design of a novel electrochemical biosensor, in which graphene and membrane proteins would serve as transducer and biological recognition elements, respectively. Graphene is used as transducer because of its unique and intriguing properties, namely surface area, electrical conductivity, ultra high electron mobility, wide electrochemical potential window, low charge-transfer resistance, and reduction of overvoltage. All these properties are responsible for the enhancement of the direct electron transfer between the graphene surface and the membrane proteins. Membrane proteins are the chosen biosensing element for this study since they represent almost 60% of all human protein drug targets. The main problem is that the contact with electrode surface causes the denaturation of membrane proteins, so they need to be embedded in a system mimicking their native environment (i.e. the cell membrane). Supported lipid bilayers (SLBs) are widely used as artificial cell membranes for biophysical studies and nano-biotechnology applications. They are most often generated starting from a liposome solution in which surfaces are incubated for a certain period of time. SLBs form preferentially and are functional on more hydrophilic substrates, whereas graphene surfaces are highly hydrophobic, and so they need to be modified.