Imaging of DNA hybridization on microscopic polypyrrole patterns using scanning electrochemical microscopy (SECM): the HRP bio-catalyzed oxidation of 4-chloro-1-naphthol.

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.