In our work we investigate the development of a novel electrochemical biosensor using graphene as transducer and electroactive membrane proteins as biological recognition elements. Graphene is used as transducer because of its unique properties, namely high 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 graphene and the membrane proteins. Membrane proteins are the chosen biosensing element since they are the key factors in cell metabolism, e.g., in cell-cell interactions, signal transduction, and transport of ions and nutrients. Thanks to this important function, membrane proteins are a preferred target for pharmaceuticals, with about 60% of consumed drugs addressing them. 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, the supported lipid bilayers (SLBs). This study is focused on the synthesis of graphene through chemical vapour deposition (CVD), on the surface treatments of graphene through a mild oxidation – to improve its biocompatibility – and on the investigation of its interaction with SLBs. High quality graphene is synthetized by chemical vapour deposition and it is characterized by using scanning electron microscopy (SEM) imaging, Raman spectroscopy and by measuring the water contact angles (WCAs) before and after surface treatments. The interaction of graphene with lipids (DOPC - 1,2-dioleoyl-sn-glicero-3-phosphocholine), in particular the formation of SLBs is investigated via electrochemical impedance spectroscopy (EIS), which is a valuable tool for characterizing surface modifications, such as those occurring during the immobilisation of biomolecules (i.e. lipid membrane) on the transducer. A way of interpretation of EIS data is to use an equivalent circuit: its parameters are determined from the best fitting of theoretically calculated impedance plots to experimental ones.

Study of graphene - supported lipid bilayers interaction for applications in novel electrochemical biosensors

Martina Pittori;Mariagabriella Santonicola
2016

Abstract

In our work we investigate the development of a novel electrochemical biosensor using graphene as transducer and electroactive membrane proteins as biological recognition elements. Graphene is used as transducer because of its unique properties, namely high 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 graphene and the membrane proteins. Membrane proteins are the chosen biosensing element since they are the key factors in cell metabolism, e.g., in cell-cell interactions, signal transduction, and transport of ions and nutrients. Thanks to this important function, membrane proteins are a preferred target for pharmaceuticals, with about 60% of consumed drugs addressing them. 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, the supported lipid bilayers (SLBs). This study is focused on the synthesis of graphene through chemical vapour deposition (CVD), on the surface treatments of graphene through a mild oxidation – to improve its biocompatibility – and on the investigation of its interaction with SLBs. High quality graphene is synthetized by chemical vapour deposition and it is characterized by using scanning electron microscopy (SEM) imaging, Raman spectroscopy and by measuring the water contact angles (WCAs) before and after surface treatments. The interaction of graphene with lipids (DOPC - 1,2-dioleoyl-sn-glicero-3-phosphocholine), in particular the formation of SLBs is investigated via electrochemical impedance spectroscopy (EIS), which is a valuable tool for characterizing surface modifications, such as those occurring during the immobilisation of biomolecules (i.e. lipid membrane) on the transducer. A way of interpretation of EIS data is to use an equivalent circuit: its parameters are determined from the best fitting of theoretically calculated impedance plots to experimental ones.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11573/935105
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