Miniaturized ultrathin slab gel electrophoresis with thermal lens microscope detection and its application to fast genetic diagnosis

A miniaturized ultrathin slab gel electrophoresis (MUSGE) apparatus was dev eloped, and fast separation of DNA fragments was obtained using it. To obta in sufficient separation efficiency in a limited space, a discontinuous buf fer system was used. In general, it is difficult to cast a discontinuous ul trathin slab gel of adequate quality. However, the miniaturized resolving g el could be cast by taking advantage of the "capillary phenomenon" of the u ltrathin channel, A gradient plate was used to control the height of the re solving gel and to form a clear interface between the concentrating gel and the resolving gel. This method was used to cast multiple gels simultaneous ly and reproducibly. The gradient plate also facilitated sample introductio n, which was carried out by using a micropipet. A 25-mm-long and 80-mu m th ick-resolving gel was used to separate the 100-base pair ladder DNA within 10 min. Bandwidth was reduced to 100-200 mu m, thus improving the number of theoretical plates to 22000, which was comparable to that in conventional slab gel electrophoresis even though the migration distance was reduced to 1/10 Satisfactory lane-to-lane reproducibility (RSD < 1.0%, n = 6) and gel- to-gel reproducibility (RSD < 2.7%, n = 4) were obtained. Finally, the MUSG E apparatus was successfully applied to get a rapid genetic diagnosis.