Protein market pellets and method of making and using the same

#The invention relates to a protein markers for protein gel electrophoresis.

#A device used for calibrating protein gel electrophoresis separations is a liquid protein marker. A liquid protein marker includes at least one protein of known molecular weight marked with a tracking dye and ionic components to provide electrical conductance. The protein migrates out of the mixture under the influence of an electrical field at the same rate as the ions. After gel electrophoresis, the migration pattern of a number of protein samples is compared to the migration pattern of the liquid protein marker to determine size or other characteristics of the protein samples.

#A problem with liquid protein markers is that they have to be pipetted into wells of the reservoirs. This pipetting step can be burdensome and adds time to the overall process, especially if a large number of gels are loaded (e.g., loading eight gels simultaneously with 96-well automated loaders). Another problem is that with wide wells such as 7.5 mm wide wells, a large volume of the liquid protein marker solution must be added to provide sufficient sensitivity during electrophoresis of the marker. This can significantly increase the cost of a gel run because of the expense of the marker solution. Also, marker solutions must be kept at such low temperatures that they freeze. Repeated freeze/thaw cycles of the marker solution can cause degradation of proteins. A further problem is that only one marker solution can be added per well because multiple marker solutions would mix, giving confusing results.

#FIG. 1 is a perspective view of an embodiment of a thin-gel electrophoresis assembly with an embodiment of a protein marker pellet shown fixed to a substrate.

#FIG. 2 is a top plan view of an embodiment of multiple protein marker pellets on substrates.

#With reference to FIG. 1, an embodiment of a thin-film gel electrophoresis assembly 100 is shown. The electrophoresis assembly 100 may be used with an embodiment of a protein marker pellet of the present invention. The electrophoresis assembly 100 will first be described, followed by a description of an embodiment of a protein marker pellet of the present invention.

#The thin-film gel electrophoresis assembly 100 includes a support frame 110 that carries a gel sandwiched between a first, inner thin-film member 120 and a second, outer thin-film member 130. A reservoir 140 is detachably mounted to a top 150 of the support frame 110. The thin-film gel electrophoresis assembly 100 shown is part of a vertical, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE) gel electrophoresis system. The protein marker pellet described in detail below may be used with electrophoresis systems other than vertical, SDS PAGE gel electrophoresis systems.

#The reservoir 140 includes an upper portion 160, and intermediate portion 170, and a lower portion 180 that gradually tapers in thickness from a wide, open top 190, where samples are introduced, to a narrow, open bottom 200, where the samples electrophoretically migrate from a first gel in the reservoir 140 to a second gel sandwiched between the thin-film members 120, 130. The upper portion 160 has a trough-like configuration. The lower portion 180 include a plurality of divided sample wells 202. Mounting mechanisms 210, 220 extend from opposite ends 230, 240 of the reservoir 140. Each mounting mechanism 210, 220 includes a first, small, front laterally protruding member 250 and a parallel second, large, rear laterally protruding member 260.