Electrophoresis sequencing apparatus

Abstract

A compact, low cost, automated electrophoresis apparatus provides for the optical detection of multiple DNA samples. A substantially cylindrical gel cartridge houses multiple sample lanes that are sealed on the outer periphery by a shrink tube, which allows for straightforward gel casting, as well as for the pre-casting of sequencing gels. The radial column design of the gel cartridge also facilitates the use of a light source to illuminate one or more sample lanes at the same time. The radial column design further provides for an increased sample lane depth that allows for reading through a greater optical path length of the migrated samples, yielding greater optical signal strength, and an increased signal to noise ratio. The gel lanes can be designed to vary in depth as a function of longitudinal length, allowing for a variable current density. Additionally, this radial design allows for different types of optical detection techniques to be performed on the sample, including transmittance and fluorescence. A system of cooling channels incorporated into the radial column design allows for a coolant to be recirculated in the cooling channels between the actual running sample lanes for better lane-to-lane thermal control. This cooling system allows higher operating voltages and facilitates the use of multiple thermal zones, as required, for instance, for single-strand conformation polymorphism (SSCP) applications.