Technical Field

The present invention relates to a grooved gel, and more specifically to a grooved gel arrangement wherein distortions and spreading (diffusion) of pro¬ teins within the gel are eliminated or at least mini¬ mized.

Background Art The human body contains proteins which are remark¬ ably diverse in size, architecture and biological responsibility. They range in molecular weight from a few thousand to more than a million. They may be stretched into long, strong fibers or coiled into com- pact globules. They exist in a variety of different forms, such as: structural proteins, connective-tissue proteins, contractile muscle proteins, enzymes, hor¬ mones, antibodies, transport molecules (such as the hemoglobin which carries oxygen to the cells), storage proteins, cell-surface receptors, and the- like.

One of the traditional methods for separating proteins for the purpose of identification is electro¬ phoresis, which simply means "carried by electricity". Proteins from, for example, a blood or urine sample, appropriately prepared, can be separated in an electrical field because each different type of protein is carried along at a slightly different speed, depending on the net electrical charge of a given molecule. This method, one-dimensional electrophoresis, has proven to be an extremely powerful scientific tool.

Ol-.iPI

In the mid-1970s, two-dimensional techniques for separating proteins were developed. One such technique was designated "gel electrophoresis", and comprises a technique which differentiates proteins moving through a gel into clearly delineated bands which can be iden¬ tified as specific proteins or groups of proteins. The method separates proteins moving in one direction by their electrical charge into single rows. Then, the gel is turned on its side, and a detergent is added to interact electrically with the proteins, causing them to move in a second direction, by which movement in the second direction they are sorted out by size. More¬ over, when the two-dimensional gel is stained with a dye, the result is a grid-like series of protein "spots", the columns being separated horizontally by their electrical charge, and vertically by size. Such a "protein map" can separate a great many more proteins from a sample than is possible with one-dimensional electrophoresis. Gels utilized in the latter manner can then be scanned, the gel being divided into a very large number (for example, one or two million) tiny squares, each square being examined and analyzed by well-known com¬ puter information processing techniques. Once each square is analyzed in detail, the corresponding data can be stored for future recall, enhancement, and dis¬ play. Moreover, the density data can be converted into color differences for easier discrimination and viewing on a computerized display. In addition, the "background noise", typically present in such scan- derived information, can be filtered out by a computer system, and distortions in the gel itself can also be corrected. A detailed treatment of such two- dimensional electrophoretic procedures is set forth in

cτι

"High Resolution Two-Dimensional Electrophoresis of Proteins", by Patrick H. O'Farrell, The Journal Of Biological Chemistry, Volumn 250, No. 10 (May 25, 1975), pages 4007-4021. It should be recognized that, for the purpose of gel analysis using computerized scanning, it is important that resolution be minimized to the greatest extent possible. On the other hand, attempts to mini¬ mize resolution, have in the past, been thwarted by the occurrence of the phenomenon known as diffusion

(spreading). That is, during the first-dimensional phase of the electrophoretic procedure, the proteins are distributed latitudinally across the gel, and then, during the second-dimensional phase of the procedure, the proteins are distributed longitudinally through the gel along respective paths or channels. During the latter procedure, diffusion (spreading) of the proteins can take place, thus providing a distorted distribution of the proteins, and this adversely affects the resolu¬ tion which can be achieved by the gel scanning proce¬ dure.

In addition, during the fabrication of gels, the physical gel itself often becomes distorted, and this adversely affects the process by means of which the proteins are distributed latitudinally and longitudi¬ nally within the gel during the electrophoretic proce¬ dure. This amounts to a further cause of adverse dif¬ fusion (spreading) of the protein within the gel, thus further adversely affecting the data derived from scan¬ ning of the gel during the computer scanning phase of operation.

Disclosure of the Invention

The present invention relates to a grooved gel,

and more particularly to a grooved gel arrangement in which distortion and spreading (diffusion) of protein spots within the gel are eliminated or at least mini¬ mized. More specifically, according to the invention, a plastic backing for holding the gel is formed with grooves disposed in it, so that, when the gel is dis¬ posed on the plastic backing, the gel fills in the grooves in the plastic backing, thus forming a grooved gel arrangement. As a result of utilization of a grooved plastic backing during the procedure of fabricating the gel, distortion of the physical gel itself is prevented or at least minimized. This, in turn, prevents diffusion (spreading) of protein, during the electrophoretic procedure, and thus resolution is reduced and mini¬ mized.

Once the gel is formed on the grooved plastic backing, a glass or plastic top cover or plate can be placed over the gel, and the gel can be appropriately arranged so that a conventional electrophoretic proce¬ dure can be carried out. During the latter procedure, proteins which would otherwise tend to diffuse or spread during their dispersion longitudinally along the gel will not do so, thus preventing distorted results from being obtained during the computerized scanning of the gel.

Therefore, it is a primary object of the present invention to provide a grooved gel, and more particu¬ larly a grooved gel arrangement. It is an additional object of the present invention to provide a grooved gel arrangement in which distortion of the physical gel itself, which would otherwise be introduced during the fabrication phase.

is prevented.

It is an additional object of the present inven¬ tion to provide a grooved gel arrangement in which diffusion (spreading) of proteins during an electro- phoretic procedure is precluded or minimized.

The above and other objects that will hereinafter appear, and the nature of the invention, will be more clearly understood by reference to the following des¬ cription, the appended claims, and the accompanying drawings.

Brief Description of the Drawings

FIGURE 1 is a perspective view of a grooved gel arrangement according to the present invention.

FIGURE 2 is a top view of the grooved base plate utilized in the grooved gel arrangement of the present invention.

FIGURE 3 is a front view of the grooved gel arrangement of the present invention.

Best Mode for Carrying Out the Invention The invention of the application will now be more fully described with reference to the various figures of the drawings.

As seen in FIGURE 1, which is a perspective view of the grooved gel arrangement of the present inven- tion, the grooved gel arrangement 10 basically com¬ prises a grooved base plate 12 and a top plate 14. A given portion 16 of the base plate 12 has grooves dis¬ posed longitudinally for receiving a gel disposed thereon. Preferably, the grooves are arranged in a very fine array, with the spacing between the grooves being on the order of fraction of a millimeter.

The process of constructing a grooved gel arrange¬ ment according to the present invention will now be described with reference to FIGURE 2, which is a top view of the grooved base plate 12. The grooved base plate 12 is preferably made of plastic or other similar non-conductive material and, as previously mentioned, contains a portion 16 having grooves disposed thereon with very close spacing. With the grooved base plate positioned in a horizontal posture, a gel is disposed thereon in such a way that the gel fills in the grooved spaces contained in the portion 16 of the base plate 12.

FIGURE 3 is a front view of the grooved gel arrangement of the present invention. As seen therein, once the gel is disposed on the grooved portion 16, it fills in the grooves, thus forming a uniform, stable and well-supported grooved gel structure on the base plate 12.

As further shown in FIGURES 1 and 3, a top plate 14 is then positioned on top of the grooved base plate 12 so as to sandwich the gel therebetween. The top plate 14 is, preferably, plastic, glass, or other non- conductive and transparent material.

Needless to say, some sort of access means or opening (not shown) must be provided in the grooved gel arrangement so that, once the top plate 14 is posi¬ tioned on the grooved base plate 12, with the gel sand¬ wiched therebetween in the grooved portion 16, protein samples can be inserted at a given point in the portion 16. Once such protein sairples are inserted into the grooved portion 16, the electrophoretic procedure can be carried out. That is to say, during the first phase, proteins can be separated according to iso- electric point by isoelectric focusing in the first

O-.'.ri

dimension, and then, during the second phase, proteins are separated according to molecular weight by electro¬ phoresis in the second dimension.

More specifically, as previously mentioned, during ^ the first phase, gel electrophoresis is carried out by means of applying an electric field latitudinally across the gel (that is, in a direction from left to right in FIGURES 1-3). This differentiates proteins moving through the gel into clearly delineated bands 10 which can be identified as specific proteins or groups of proteins. The technique seprates proteins moving in the single direction, by virtue of their electrical charge, into single rows.

Then, the gel is turned on its side, and a further 15 electrophoretic procedure is carried out (for example, a detergent can be added to interact electrically with the proteins in each of the single rows). The proteins in each row are caused to move in a second direction, longitudinally across the gel (that is, from bottom to 20 top in FIGURE 2), and the proteins are, in this manner, sorted out by size.

Finally, as mentioned previously, if the two- dimensional gel is then stained with a dye, the result is a grid-like series of protein "spots", with the

25 columns separated horizontally by electrical charge, and vertically by size. This "protein map" can then be submitted to a computerized scanning procedure, by means for which a scanner, connected to a computer system, can scan the surface of the grooved gel (in a

30 manner similar to the way in which a television is raster-scanned) so as to develop data pertaining to the "protein map". With reference to FIGURE 3, this scan¬ ning can take place by virtue of the transparency of the top plate 14 (which, as previously mentioned, is

preferably of plastic, glass or other transparent, non- conductive material) .

It is to be further noted that, during the elec¬ trophoretic procedure, and specifically during the second phase thereof, proteins are travelling longi¬ tudinally along the grooved portion 16 (FIGURE 2) of the base plate 12 (from bottom to top, as seen in FIGURE 2). Since the grooved base plate 12 was employed during the fabrication procedure in forming the gel, the gel will be of a uniform construction, and will have very little or no physical distortion. This serves to preclude diffusion or spreading of the pro¬ teins as they travel longitudinally along the grooved portion 16. In addition, by virtue of the presence of the grooves in the grooved portion 16, during the second phase of the electrophoretic procedure, the natural diffusion or spreading of the proteins as they travel longitudinally along the grooved portion 16 will be minimized or eliminated by virtue of the channellizing an effect of the grooves contained in the grooved por¬ tion 16. That is to say, the walls of the grooves contained in the grooved portion 16 act to inhibit latitudinal diffusion (spreading) of the protein as it s travelling in a longitudinal direction (from bottom to top in FIGURE 2) along the grooved portion 16 of the base plate 12.

While preferred forms and arrangements have been shown in illustrating the invention, it is to be clearly understood that various changes in detail and arrangement may be made without departing from the spirit and scope of this disclosure.

CMΓI