DOE Human Genome Program Contractor-Grantee Workshop VIII
February 27-March 2, 2000  Santa Fe, NM

43. The Use of Electrode Arrays for the Synthesis of Biomolecular Affinity Probes

Francis Rossi, Christopher Ashfield, Karl Maurer, and Donald Montgomery

CombiMatrix Corporation, 887 Mitten Road, Suite 200, Burlingame, CA 94010

frossi@combimatrix.com

We have developed an active semiconductor chip composed of over 1000 individually addressable electrodes that is used to synthesize microarrays of biomolecular affinity probes. Arrays are prepared by coating the semiconductor chip with a porous polymer support in which synthesis occurs. The underlying electrodes are used to electrochemically generate reagents from inert precursors. By switching on individual electrodes, or patterns of electrodes, reactions can be conducted at defined locations of the chip.

The technology has been successfully used to prepare DNA oligonucleotide probe arrays from commercially available reagents. To synthesize an array, electrodes are biased as anodes at defined locations. This generates acid, which removes the DMT protecting group from the 5'-hydroxyl group of nascent oligonucleotides. Extension of the deprotected hydroxyl group using standard DNA phosphoramidite reagents adds the next base of the oligonucleotide.

We are now extending this technology to the synthesis of peptide probe arrays for the identification and analysis of gene products. Peptides were prepared by first immobilizing an Fmoc-protected amino linker to the porous polymer support. The amino groups were deprotected at the desired locations with an electrochemically generated base. The resulting free amines were reacted with an activated Fmoc-protected amino ester using conventional techniques to give peptides.