Surface Bio-Functionalization of Boron Doped Diamond
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0956-J09-26
Surface Bio-Functionalization of Boron Doped Diamond Mathias Bonnauron1, Charles Agnes2,3, Pascal Mailley2, Jean-Charles Arnault4, Jacques de Sanoit1, Christine Mer1, Licinio Rocha1, Philippe Bergonzo1, Milos Nesladek1, Frank Omnes3, and Omar Elmazria5 1 CEA-LIST, CEA-Saclay, Centre d'Etudes de Saclay, Bât 451, Gif-sur-Yvette, F-91191, France 2 DRFMC-SPrAM, CEA-Grenoble, Centre d'étude de Grenoble, 17 r Martyrs, Grenoble - Cedex 9, F-38054, France 3 CNRS-LEPES, UPR 11, CNRS, Av. des Martyrs, BP166, Grenoble - Cedex 9, F-38042, France 4 CEA-DRECAM, CEA-Saclay, Centre d'Etudes de Saclay, Bât 462, Gif-sur-Yvette, F-91191, France 5 LPMIA, UMR CNRS 7040, Université Henri POINCARRE, Faculte des Science et Techniques, Université Henri Poincaré, Boulevard des Aiguillettes, B.P. 239, Vandoeuvre Lès Nancy CEDEX, F-54506, France ABSTRACT Biotin was grafted onto boron doped nanocrystaline diamond electrode through a fourstep-chemical process. The first grafting step was the electro-chemical reduction of p-4,nitro diazonium salts. The surface functionalization was characterized using X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) as well as fluorescence analysis. XPS analysis and spectrum interpolation led to the identification of the species on the surface in order to highlight the surface coverage and attachment of the grafted film. AFM measurements highlighted the non-mononuclear aspects of the diazonium electrografting. Fluorescence measurements with avidin recognition demonstrated the efficiency of the grafting. INTRODUCTION Diamond exhibits several attractive properties for bio-sensing applications. In particular, the high bio-inertness of diamond, high electrochemical stability, and optical transparency provide diamond with high interests for electrochemical or optical biodetection. In this study we more particularly focus on the surface functionalization of metallicconductive boron-doped diamond electrodes. Details on the growth and properties used for the film preparation are given, together with the surface attachment of biotin used here as a biological model. The aim is the description of the first steps of the grafting process on boron doped diamond to investigate the grafting parameters such as primers density and surface distribution. The characterisation of the surface attachments were conducted using electrochemical methods, together with X-ray Photoelectron Spectroscopy (XPS) in order to confirm (i) the presence of diazonium electro-grafting and (ii) the electrochemical activation of the primers. Biotin was then anchored to the electrochemically activated diamond surface through an appropriate spacer arm. Here the effectiveness of the diamond surface biotinilation was addressed using fluorescence microscopy of a biotin-avidin recognition complex using streptavidin-phycoerythrin conjugate.
This study serves as a demonstrator for further diamond modification with more complex recognition structures such as proteins or enzymes in the view of high frequency SAW or electrochemica
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