Construction and evaluation of a capillary array DNA sequencer based on a micromachined sheath-flow cuvette

A capillary array electrophoresis DNA sequencer is reported based on a micr omachined sheath-flow cuvette as the detection chamber. This cuvette is equ ipped with a set of micromachined features that hold the capillaries in pre cise registration to ensure uniform spacing between the capillaries, in ord er to generate uniform hydrodynamic flow in the cuvette. A laser beam excit es ail of the samples simultaneously, and a microscope objective images flu orescence onto a set of avalanche photodiodes, which operate in the analog mode. A high-gain transimpedance amplifier is used for each photodiode, pro viding high duty-cycle detection of fluorescence.