Large microchannel array fabrication and results for DNA sequencing

We have developed a process for the production of microchannel arrays on bonded glass substrates up to 14 X 58 cm, for DNA sequencing. Arrays of 96 and 384 microchannels, each 46 cm long have been built. This technology offers significant advantages over discrete capillaries or conventional slab-gel approaches. High throughput DNA sequencing with over 550 base pairs resolution has been achieved. With custom fabrication apparatus, microchannels are etched in a borosilicate substrate, and then fusion bonded to a top substrate 1.1 mm thick that has access holes formed in it. SEM examination shows a typical microchannel to be 40 X 180 micrometers by 46 cm long; the etch is approximately isotropic, leaving a key undercut, for forming a rounded channel. The surface roughness at the bottom of the 40 micrometer deep channel has been profilometer measured to be as low as 20 nm; the roughness at the top surface was 2 nm. Etch uniformity of about 5% has been obtained using a 22% vol. HF/78% Acetic acid solution. The simple lithography, etching, and bonding of these substrate enables efficient production of these arrays and extremely precise replication from master masks and precision machining with a mandre