title: Imaging of DNA hybridization on microscopic polypyrrole patterns using scanning electrochemical microscopy (SECM): the HRP bio-catalyzed oxidation of 4-chloro-1-naphthol.
abstract: We illustrate in this paper the successful combination of the direct and feedback mode of scanning electrochemical microscopy (SECM) for the writing of oligonucleotide patterns on thin gold films alongside the imaging of DNA hybridization. The patterning process was achieved using the direct mode of SECM, where the electrical field established between the SECM tip and the gold interface was used to drive the local deposition of micrometre sized polypyrrole spots to which a 15(mer) oligonucleotide (ODN) strand was linked covalently. Imaging of the deposited polypyrrole-ODNs was achieved by means of the feedback mode of SECM using Ru(NH(3))(6)(3+) as the mediator. The detection of the hybridization reaction of the ODN probes with their biotinylated complementary strands using SECM was possible after subsequent reactions with streptavidin and biotinylated horseradish peroxidase (HRP). The HRP-biocatalyzed oxidation of 4-chloro-1-naphthol (1) in the presence of H(2)O(2), and the precipitation of the insoluble product 4-chloro-1-naphthon (2) on the hybridized areas on the gold film caused a local alteration of conductivity. Such a change in conductivity was sensitively detected by the SECM tip and allowed imaging of DNA arrays in a fast and straightforward way.
authors.affiliation: Groupe CREAG, UMR CNRS/CEA/UJF 5819, DRFMC/SI3M, CEA, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Fortin
authors.forename: Pascale
authors.initials: P
authors.lastname: Mailley
authors.forename: Loic
authors.initials: L
authors.lastname: Lacroix
authors.forename: Sabine
authors.initials: S
authors.lastname: Szunerits
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D002384:Catalysis; D004247:DNA / Q000378:metabolism*; D004563:Electrochemistry / Q000379:methods; D006046:Gold; D006735:Horseradish Peroxidase / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D009284:Naphthols / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D010084:Oxidation-Reduction; D011108:Polymers / Q000378:metabolism; D011758:Pyrroles / Q000378:metabolism
chemical_list: D009284:Naphthols; D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; C025917:4-chloro-1-naphthol; D006046:Gold; D004247:DNA; D006735:Horseradish Peroxidase