Improved separation in horizontal protein SDS-PAGE with double-deck flat electrodes and a field inversion gel electrophoresis module

Abstract

The horizontal flatbed electrophoresis method is employed to separate protein samples, providing greater flexibility for various electrophoretic applications and easier sample loading compared to its vertical counterpart. In the currently available equipment setup, cathode and anode electrodes are positioned on top of a gel at each end. Since an electric field enters the gel from the top, its strength gradually weakens from the top to the bottom of the gel. When examining the interior of gels following electrophoretic separation, the uneven electric field causes the protein bands to lie down forward in the direction of migration, leading to an increase in bandwidth. This issue has remained unaddressed for several decades. To address this problem, new clamp-shaped and double-deck electrodes were developed to apply an electric field simultaneously from both the top and bottom of the gel. Both of these new electrodes facilitated the formation of perpendicular protein band shapes and enhanced resolution at a comparable level. Due to their ease of use, double-deck electrodes are recommended. By combining these new electrodes with the field inversion gel electrophoresis (FIGE) technique, the protein bands could be focused and aligned nearly vertically, resulting in the highest level of electrophoretic resolution. Our electrodes are compatible with polyacrylamide gels of varying sizes, buffer systems, and sample well formats. They can be easily manufactured and seamlessly integrated into existing laboratory instruments for practical use.