For the first time, a microchannel was photochemically patterned with a functional linker. This simple method was developed for the site-specific attachment of DNA via this linker onto silicon oxide surfaces (e.g., fused silica and borosilicate glass), both onto a flat surface and onto the inside of a fused silica microchannel. Sharp boundaries in the micrometer range between modified and unmodified zones were demonstrated by the attachment of fluorescently labeled DNA oligomers. Studies of repeated hybridization- dehybridization cycles revealed selective and reversible binding of cDNA strands at the explicit locations. On average, ∼7x 1011 fluorescently labeled DNA molecules were hybridized per square centimeter. The modified surfaces were characterized with X-ray photoelectron spectroscopy, infrared microscopy, static contact angle measurements, confocal laser scanning microscopy, and fluorescence detection (to quantify the attachment of the fluorescently labeled DNA).