Regensburg 2007 – scientific programme

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BP: Fachverband Biologische Physik

BP 19: Biosensors and Biofunctionalized Systems

BP 19.4: Talk

Wednesday, March 28, 2007, 16:15–16:30, H43

Chemical Grafting of Biphenyl Self-Assembled Monolayers on Diamond for the Electro-Addressing of Proteins — •Simon Lud¹, Florian Spirkl¹, Marin Steenackers², Rainer Jordan², Paola Bruno³, Dieter M. Gruen³, Stefan Neppl⁴, Peter Feulner⁴, Jose A. Garrido¹, and Martin Stutzmann¹ — ¹Walter Schottky Institut, Technische Universität München — ²Lehrstuhl für Makromolekulare Stoffe, Technische Universität München — ³Materials Science Department, Argonne National Laboratory — ⁴Physics Department E20, Technische Universität München

We have explored the formation of self-assembled monolayers (SAMs) of 4’-nitro-1,1-biphenyl-4-diazonium tetrafluoroborate (NBD) onto ultrananocrystalline diamond (UNCD) thin films. In contrast to the established method to modify diamond and diamond like substrates by electrografting, the SAM was formed from the saturated solution of NBD in acetonitrile by spontaneous chemical grafting. Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and near edge X-ray absorption fine structure spectroscopy (NEXAFS) have been used to verify the direct covalent attachment of the 4’-nitro-1,1-biphenyl (NB) SAM on the diamond substrate via stable C-C bonds. The results confirm the presence of a very stable, homogeneous, and dense monolayer. Quantitative analysis by XPS, NEXAFS, and CV has confirmed the presence of a densely packed monomolecular layer with a grafting density of 4.5-5.3 x 10⁻¹⁰mol/cm², equivqalent to a nominal area of 31-37 Ų/molecule.