Effect of buffer flow on DNA separation in a microfabricated electrophoresis system.
An adequate buffer reservoir is one essential component of an electrophoresis system, providing current carrying ions and maintaining constant pH. In a microfabricated DNA separation system with on-chip electrodes, the amount of buffer used is limited by the design of the device; the buffer continuity can be easily disturbed by the production of bubbles. Continuously flowing 1 x Tris-borate-EDTA (TBE) buffer over the electrodes at the cathodic end solves both problems. This flow increases the resolution for ssDNA primer separations (21 and 25 bases) to a maximum value of 1.4 within a distance of 1.2 cm, about four times higher than that without flow. Similar improvement has been achieved for dsDNA separation (20 bp ladder; BioRad) at a distance of only 0.4 cm, giving baseline resolution for bands from 20 to 240 bp. We have also investigated the effect of buffer concentration on resolution, and no similar improvement can be obtained by merely increasing the buffer concentration without flow.
Chen
Zheng
Z
Department of Chemical Engineering, The University of Michigan, Ann Arbor, MI 48109-2136, USA.
Burns
Mark A
MA
D002021:Buffers; D004247:DNA / Q000302:isolation & purification*; D004277:DNA, Single-Stranded / Q000302:isolation & purification; D046209:Electrophoresis, Microchip / Q000295:instrumentation / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D012212:Rheology
D002021:Buffers; D004277:DNA, Single-Stranded; D004247:DNA