Electrochemical and Photochemical Patterning of Oxidized Boron-Doped Diamond Electrodes
|Sabine Szunerits 1, Paolo Actis 1, Rabah Boukherroub 2|
1. Institute National Polytechnique de Grenoble (INPG), 1130, rue de la piscince, Saint Martin d'Hères 38402, France
The ability to pattern surfaces with micro- and nanometer sized structures is currently a significant area of research. Lithographic and scanning probe microscopy techniques have been widely used to show the feasibility and the limits employing these different approaches. Micropatterned surfaces are of interest as they allow the controlled deposition of liquids or cells and site-specific immobilization of chemical and biological molecules, a critical step in many assays including diagnostic analysis, high throughput screening, and bioelectronic sensing. Boron-doped diamond (BDD) substrates have emerged over the years as attractive electrode materials and have gained remarkable interest for various applications due to their high chemical stability, good electrical conductivity, large potential window in aqueous electrolytes, and biocompatibility. Boron-doped diamond (BDD) electrodes are in addition interesting interfaces for the formation of micropatterns. The present work describes different approaches to incorporate electro- or photoactive groups on BDD for biomolecules immobilization. First, pyrrole-terminated BDD surface was prepared by chemical functionalization of oxidized BDD surface with N-(3-trimethoxysilylpropyl)pyrrole (TMPP). The reaction produces an organic layer covalently attached to the surface and bearing terminal electroactive pyrrole groups. The covalent linking of pyrrole units on the BDD surface allows formation of strongly adhesive conducting polymer films through electropolymerization. The micro- and nanopatterning of BDD with polypyrrole was achieved using either the direct mode of Scanning Electrochemical Microscope (SECM) or the newly developed electrochemical Scanning Near-field Optical Microscope (E-SNOM). The nanopatterning of BDD with polypyrrole using E-SNOM was achieved by constraining the current lines between ITO and the electro-optical tip, working as a counter electrode, by bringing the electro-optical probe into the near-field of the BDD interface. The essence of this deposition method is based on the generation of high concentrations of pyrrole radical cation monomers in the gap between the BDD electrode and the electro-optical tip, working in this case as a counter electrode. Depending on the method used polypyrrole dots with diameters in the range of 1-250 µm are electrogenerated. A second approach is based on the direct immobilization of biological molecules via photochemical reaction with surface-bound benzophenone.
1. P. Actis, M. Manesse, C. Nunes-Kirchner, G. Wittstock, Y. Coffinier, R. Boukherroub, S. Szunerits, Phys. Chem. Chem. Phys., 2006, 8, 4924.
2. S. Szunerits, N. Shirahata, P. Actis, J. Nakanishi, R. Boukherroub, Chem. Commun., 2007, 2793.
Presentation: Keynote lecture at SMCBS'2007 International Workshop, by Sabine Szunerits
See On-line Journal of SMCBS'2007 International Workshop
Submitted: 2007-08-15 12:19 Revised: 2009-06-07 00:48