DNA separations in microfabricated devices with automated capillary sampleintroduction

A novel method is presented for automated injection of DNA samples into mic rofabricated separation devices via capillary electrophoresis. A single cap illary is used to electrokinetically inject discrete plugs of DNA into an a rray of separation lanes on a glass chip. A computer-controlled micromanipu lator is used to automate this injection process and to repeat injections i nto five parallel lanes several times over the course of the experiment. Af ter separation, labeled DNA samples are detected by laser-induced fluoresce nce. Five serial separations of g-carboxyfluorescein (FAM)-labeled oligonuc leotides in five parallel lanes are shown, resulting in the analysis of 25 samples in 25 min. It is estimated that approximately 550 separations of th ese same oligonucleotides could be performed in one hour by increasing the number of lanes to 37 and optimizing the rate of the manipulator movement. Capillary sample introduction into chips allows parallel separations to be continuously performed in serial, yielding high throughput and minimal need for operator intervention.