Microfabrication Technology for the Production of Capillary Array Electrophoresis Chips

Improvements in the fabrication, sample handling and electrical addressing of capillary array electrophoresis (CAE) chips have permitted the development of high density, high-throughput devices capable of analyzing 48 samples in about 20 minutes. The fabrication of high density capillary arrays on 10 cm diameter substrates required the characterization of glasses that yield high quality etches and the development of improved sacrificial etch masks. Using these improved fabrication techniques, high-quality, deep channel etches are routinely obtained. Methods for bonding large area substrates and for drilling arrays of 100 or more access holes have also been developed. For easier sample introduction, we use an array of sample wells fabricated from an elastomeric sheet. The practicality of these technologies is demonstrated through the analysis of 12 DNA samples in parallel on a microfabricated CAE chip, the development of methods for injecting multiple samples onto a single capillary without cross contamination, and the operation of a microfabricated array of 12 capillaries with 4 sample injections per capillary that can analyze 48 samples.