Electrochemically directed synthesis of oligonucleotides for DNA microarray fabrication.

We demonstrate a new method for making oligonucleotide microarrays by synthesis in situ. The method uses conventional DNA synthesis chemistry with an electrochemical deblocking step. Acid is delivered to specific regions on a glass slide, thus allowing nucleotide addition only at chosen sites. The acid is produced by electrochemical oxidation controlled by an array of independent microelectrodes. Deblocking is complete in a few seconds, when competing side-product reactions are minimal. We demonstrate the successful synthesis of 17mers and discrimination of single base pair mismatched hybrids. Features generated in this study are 40 mum wide, with sharply defined edges. The synthetic technique may be applicable to fabrication of other molecular arrays.

In situ oligonucleotide synthesis on poly(dimethylsiloxane): a flexible substrate for microarray fabrication.

In this paper, we demonstrate in situ synthesis of oligonucleotide probes on poly(dimethylsiloxane) (PDMS) microchannels through use of conventional phosphoramidite chemistry. PDMS polymer was moulded into a series of microchannels using standard soft lithography (micro-moulding), with dimensions <100 microm. The surface of the PDMS was derivatized by exposure to ultraviolet/ozone followed by vapour phase deposition of glycidoxypropyltrimethoxysilane and reaction with poly(ethylene glycol) spacer, resulting in a reactive surface for oligonucleotide coupling. High, reproducible yields were achieved for both 6mer and 21mer probes as assessed by hybridization to fluorescent oligonucleotides. Oligonucleotide surface density was comparable with that obtained on glass substrates. These results suggest PDMS as a stable and flexible alternative to glass as a suitable substrate in the fabrication and synthesis of DNA microarrays.

From innovation to market adoption in the operating room: The "CFO as customer".

Dr Egeland is senior director of business development and licensing in the Early Technologies business unit of the Minimally Invasive Therapies Group at Medtronic. Mr Rapp is an associate consultant at Pharmagellan, a biotech consultancy. Dr David is the founder and managing director of Pharmagellan.

An electrochemical redox couple activitated by microelectrodes for confined chemical patterning of surfaces.

Microelectrodes, printed as an array on the surface of a silicon chip, generate chemically active species in a solution of electrolyte held between the electrode array and a glass plate. The active species induce chemical change in molecules coupled to the surface of the glass plate, which is separated from the electrode array by a gap of several micrometers. This paper explores the nature and pattern of the induced chemical change. The patterning is discussed with respect to the electrolyte composition and the magnitude and duration of current applied to the microelectrodes. We show that under suitable conditions the active species is confined to micrometer-sized features and diffusion does not obscure the surface pattern produced.