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

Abstract

A capillary array electrophoresis DNA sequencer is reported based on a micromachined sheath-flow cuvette as the detection chamber. This cuvette is equipped with a set of micromachined features that hold the capillaries in precise registration to ensure uniform spacing between the capillaries, in order to generate uniform hydrodynamic flow in the cuvette. A laser beam excites all of the samples simultaneously, and a microscope objective images fluorescence onto a set of avalanche photodiodes, which operate in the analog mode. A high-gain transimpedance amplifier is used for each photodiode, providing high duty-cycle detection of fluorescence.

Programmable modification of cell adhesion and zeta potential in silica microchips

“…Microfluidic chip-based platforms have become increasingly popular in recent years for applications such as separation and detection, [1][2][3][4][5] PCR and/or DNA analysis, [6][7][8][9][10][11] and cell manipulation [12][13][14] owing to the speed of chip-based processes and the potential for very-large-scale integration. Using microfluidic devices for applications involving biological cells has been motivated by the potential for integrating manipulation and analysis steps, as well as increased sampling throughput and efficiency.…”

Fiber optic illumination of a poly(dimethylsiloxane) sheath flow cuvette for diode laser induced fluorescence detection in capillary electrophoresis

“…The cuvette's internal diameter is a balance between sheath‐flow buffer consumption and the requirement that any wall scattering can be spatially filtered in the detector. Cuvette materials vary but the majority are fabricated as a square cross‐section quartz tube that minimizes wall luminescence and permits transverse (90°) excitation/emission optical paths. The flat and relatively thin walls of the quartz cuvette also eliminate optical aberrations observed with on‐column detection and allow the use of large numerical aperture collection objectives to maximize S/N.…”

Novel design of multicapillary arrays for high‐throughput DNA sequencing

“…However, practical implementations of the side illumination schemes suffer from a nonuniform illumination of the capillary channels caused by reflection and refraction of the laser beam on the walls of individual capillaries. This problem was overcome with the introduction of sheath-flow [12][13][14][15][16], a method where the laser beam illuminates DNA bands when they eluted the LMCA; and laminar flow of the gel around the capillary outlets prevents broadening of the separated DNA bands. For several years sheath-flow method dominated in largescale DNA sequencing (ABI Prism-3700 machine).…”