Blotter pads for electrophoresis

Abstract

A blotter assembly for use in electrophoresis includes a block and a closed-cell silicone blotter pad adhesively attached to the block to limit inadvertent movement relative to the block.

Description

[Technical Field]

[0001] Electrophoresis is one of the most common methods for separating proteins, nucleotides, and other biological macromolecules. Methods vary depending on the medium used (e.g., agarose, acrylamide, cellulose, capillaries) and the chemical interactions utilized during the process (e.g., capillary zone, immunofixation, immunosubtraction, etc.). Many different types of electrophoresis exist, but all involve separating a sample into its individual components by applying a voltage across a medium in which the sample is placed. The electrophoretic mobility of a molecule is determined by the type of medium used, the pH, and the properties of each molecule, such as its size, shape, charge, and interactions with other molecules in the selected medium. [Background technology]

[0002] In the simplest form of electrophoresis, sample macromolecules are separated across a gel or other medium, and a stain is added, thereby revealing a sample separation profile of bands for each distinct constituent of the sample. The density and width of these bands are measured and used as quantitative and / or qualitative measures of the various macromolecules in the sample. In some instances, a single band contains signals from multiple similar but distinct macromolecules. Further identification and characterization of the macromolecules producing signals in each band can be achieved by removing selected bands and performing separate diagnostic tests.

[0003] Among the oldest clinical diagnostic tools currently in widespread use are serum protein electrophoresis (SPE) and immunofixation electrophoresis (IFE). Generally, SPE and / or IFE can be performed on a blood sample from a patient with little or no sample preparation. The sample can be placed directly into a well in an agarose gel, which can be continued for an appropriate amount of time while stained with Coomassie blue or other common protein stains, and the protein separation profile, including the characteristic absorption bands of serum proteins, can be easily observed. In some cases, the sample is first diluted or treated to avoid clotting, but no other pretreatment is necessary. The separation pattern obtained from SPE is determined by the fraction of two major types of proteins: albumin and globulin present in the sample. Both the albumin and globulin bands contain signals from many similar but distinct proteins.

[0004]

[0005] The gamma region of SPE is primarily composed of immunoglobulins, also called antibodies. Plasma cells produce immunoglobulins (also called gamma globulins), which consist of heavy chains (IgG, IgA, IgM, IgD, or IgE) and light chains (kappa or lambda) linked together. Patient samples can be placed in multiple zones or lanes on an agarose gel; after the electrophoresis step, various antisera are placed in different lanes, resulting in an antiserum-antibody reaction that indicates the presence and amount of antibodies in the sample. Stains can be used to visualize the reaction.

[0005]

[0006] Inherent in the above process is the need to remove excess liquid. It should be understood that the term "liquid" is used in this context to refer to patient samples, individually and collectively, including these sample components, substances used to dilute the sample, stains, antisera, and stain removers, as well as substances used to remove excess and / or unreacted sample, these sample components, stains, and stain removers. The presence of excess "liquid" can interfere with qualitative and quantitative analysis of results. Additionally, excess liquid must be removed from the electrophoresis and / or IFE equipment after completion of a test to allow the next test to be performed. Increasing the amount of excess liquid removed during the electrophoresis and immunofixation steps, for example, reduces the remaining liquid that must be removed between successive tests.

[0006]

[0007] Historically, blotters have been used to absorb and remove excess liquid from electrophoresis gel plates. Blotters, or more precisely, absorbent paper, sometimes called vibratous paper, are highly absorbent types of paper or other materials that absorb excess liquid material from another surface. Cotton is frequently used to manufacture absorbent paper.

[0007]

[0008] In traditional electrophoresis procedures, strips of absorbent paper are manually placed on the agarose gel, allowed to remain in place for a desired length of time to absorb excess liquid, and then manually removed. Additionally, to enhance liquid absorption, some systems place additional weights in the form of physical blocks on top of the absorbent paper. These blocks provide benefits such as maintaining contact between the blotter and the gel, thereby improving absorption rate or increasing absorption capacity, preventing the blotter from curling up away from the gel surface, and distributing a more uniform downward force on the blotter via the weights. Examples of the use of gel blocks and blotters are known and are utilized, for example, with the TITAN® GEL immunofixation procedure and the SPIFE® IgG procedure, both of which are commercially available from Helena Laboratories Corporation, Beaumont, Texas, USA, the assignee of this improved "blotter pad for electrophoresis" invention.

[0008]

[0009] The use of blotters and prior art blocks has several limitations, including, but not limited to: (a) difficulty in removing the blotter paper after use because pieces of the blotter paper can adhere to the block, (b) undesirable movement between the blotter paper and the block because the block is placed on blotter paper that has already been placed on the gel, and (c) uneven distribution of the weight of the block on the blotter paper, and therefore uneven distribution of the weight of the block and blotter paper on the gel. The use of prior art blotter paper is limited due to the manual nature of the adsorption operation. Summary of the Invention [Means for solving the problem]

[0009]

[0010] An improved blotter pad for electrophoresis is a multi-part assembly that allows for securing or attaching the pad to the blotter block and the blotter to the pad, assists in distributing weight on the blotter paper and gel to avoid undesired movement between the blotter paper and the blotter pad and between the blotter paper and the gel, and allows for easy and complete removal of the blotter paper from the pad after the adsorption step is complete.

[0010]

[0011] The improved blotter pad for electrophoresis further has a removable adhesive backing so that the blotter pad can be removed from the blotter block when necessary and a replacement blotter pad can be attached to the blotter block. The improved blotter pad for electrophoresis works with improved blotter paper having an adhesive backing that keeps the blotter paper in place to prevent accidental movement, but allows the blotter paper to be easily removed and replaced with dry blotter paper because the blotter paper is typically used only once.

[0011]

[0012] The benefits of the improved blotter blocks and pads and improved blotter papers for electrophoresis just described, along with other benefits and advantages that may be obtained through their use, will become more apparent from the following detailed description read in conjunction with the drawings. [Brief explanation of the drawings]

[0012] [Figure 1]

[0013] FIG. 1 is a perspective view of the blotter block as viewed from the top side. [Figure 2]

[0014] FIG. 2 is a perspective view of the blotter block of FIG. 1 as viewed from the bottom. [Figure 3]

[0015] 2 is another perspective view of the blotter block of FIG. 1 with a blotter pad. [Figure 4]

[0016] FIG. 1 is a perspective view showing a blotter pad. [Figure 5]

[0017] FIG. 1 is an exploded perspective view showing the blotter block and blotter pad. [Figure 6]

[0018] FIG. 1 is an exploded perspective view showing the blotter block, blotter pad, blotter paper, and a fixture or jig for properly positioning the blotter paper on the blotter pad. DETAILED DESCRIPTION OF THE INVENTION

[0013]

[0019] In the following description and explanation of the drawings, various length and width dimensions are for illustrative purposes only. Dimensions are provided in relation to the "gel area" of the electrophoresis gel, where patient samples are applied, electrophoresed, reagents are applied, and stains are applied. The dimensions are illustrative and non-limiting, also to account for the size of the equipment used in the electrophoresis system. Thus, as a non-limiting example, using SPIFE Nexus equipment manufactured by Helena Laboratories Corporation of Beaumont, Texas, USA, a typical gel area for one patient is rectangular in configuration and approximately 11.43 x 12.7 cm (4.5 x 5.0 inches). The blotter paper must have a length and width greater than the gel area. The blotter block and blotter pad must have a length and width greater than the blotter paper. The use of a rectangular gel area is also for illustrative purposes only.

[0014]

[0020] Thus, the improved blotter block 10 is shown as a generally rectangular configuration having two opposing short sides 12, 14 and two opposing long sides 16, 18. The length and width of the blotter block are approximately 13.34 x 14.99 cm (5.25 x 5.90 inches), i.e., both of which are larger than the gel area of ​​the patient sample.

[0015]

[0021] Blotter block 10 has an upper surface 20 and a lower surface 22. As explained above, the exact dimensions may vary based on the nature of the machinery used in the electrophoresis system. The sizes, shapes, proportions, and materials described in this and the following paragraphs should be understood to be merely illustrative and non-limiting. The upper surface 20 of the blotter block may be positioned closer to the short side 12 and have protrusions 24, 26 extending upwardly on the opposing sides 16, 18 of the block. These protrusions assist in the use of machinery, such as the above-referenced SPIFE Nexus, to lift and move the blotter pad. Other lifting and manipulation methods and systems, such as, but not limited to, systems using magnetic coupling, may also be used. As will be explained later, it is important that the blotter block 10 can be inverted to remove used blotter paper and replace it with new blotter paper, as well as to move the base across various gel areas on the electrophoresis plate, so that multiple samples can be adsorbed in sequence, each using new or unused blotter paper, thereby avoiding contamination between various patient samples.

[0016]

[0022] The underside 22 of the blotter block 10 has parallel, elongated raised portions 28, 30. Each raised portion extends substantially the entire length of the block, from the first end 12 to the second end 14, and is adjacent to sides 16, 18, respectively. The raised portions assist in accurately aligning the blotter pad and blotter paper, as will be described.

[0017]

[0023] In the illustrated non-limiting example, the gel plate contact area of ​​the underside 22 of the blotter block 10, excluding the area encompassed by the raised portions 28, 30, is approximately 12.7 x 13.2 cm (5.0 x 5.2 inches).

[0018]

[0024] Preferably, the blotter block may be made of stainless steel and may weigh approximately 7 pounds, which supports the natural wicking nature of the blotter paper so that the correct amount of excess liquid on the agarose gel (or other gel) can be absorbed without damaging the patient sample and / or the surface of the gel plate.

[0019]

[0025] More commonly, about 199.84 cm 2 With a gel plate contact area of ​​approximately 13.34 cm x 14.99 cm, the effective weight (force) of the gel block on the gel plate is 15.89 gm / cm 2 This becomes:

[0020]

[0026] 3 and 4, the blotter pad preferably has a thin cushion foam layer 32 having a general configuration or shape, such as a rectangle, equal to the gel contact area of ​​the underside 22 of the blotter block 10. The length and width of the foam layer are preferably greater than the length and width of the gel plate patient area but slightly less than the length and width of the underside of the block, e.g., 5.0 x 5.2 inches (13.21 x 12.7 cm). The foam layer is preferably closed-cell silicone rubber foam having a thickness of approximately 0.1875 inches (0.48 cm). The closed-cell foam layer 32 preferably has an acrylic adhesive backing on one side and is shown in FIG. 4 covered with conventional release paper 34. The release paper is removed when it is desired to attach the foam layer 32 to the underside of the blotter block 10 between the raised protrusions 28 and 30.

[0021]

[0027] If desired, the foam cushion layer is double layered, with one layer contacting the blotter block 10. In this situation, the layer contacting the underside of the blotter block 10 may be PVC (polyvinyl chloride) foam.

[0022]

[0028] Importantly, because the purpose of layer 32 is to apply appropriate pressure to the working gel area on the gel plate, the silicone rubber layer preferably has a hardness equal to or greater than that of the electrophoresis gel and conforms to the surface contours of the gel to help achieve generally uniform adhesion of the gel plate and protect the gel plate from damage, thereby helping to distribute the weight of blotter block 10 across the gel and uniform pressure (force) on the gel. Cushion layer 32 is preferably corrosion-resistant. If cushion layer 32 becomes worn or damaged, it can be removed from the underside of blotter block 10, any remaining adhesive removed from block 10, and a replacement cushion layer can be attached to underside 22 of block 10.

[0023]

[0029] Another benefit of the corrosion-resistant closed-cell layer 32 is that it protects the layer from damage when blotter paper is applied and removed, as will be further explained below.

[0024]

[0030] FIG. 5 is an exploded perspective view of the blotter block and blotter pad, generally showing the placement of blotter pad 32 on underside 22 of the blotter block between raised portion 28 and raised portion 30.

[0025]

[0031] 6 is an exploded perspective view showing the addition of blotter paper to blotter block 10. A rectangular jig or fixture 42 has opposing short sides 44, 46 and opposing long sides 48, 50. Sides 44, 46, 48, and 50 define an open rectangle. Sides 48, 50 of the jig or fixture have recesses 52, 54 that align with protrusions 28, 30 on the underside of blotter block 10. Alternatively, if desired, the jig or fixture can have protrusions and the underside 22 of block 10 can have recesses to receive these protrusions.

[0026]

[0032] Therefore, any release paper on the underside of cushion layer 32 is removed and the cushion layer is attached to the underside 22 of blotter block 10 and held in place by the adhesive portion of the cushion.

[0027]

[0033] Before or after cushion layer 32 is applied to the underside of blotter block 10, the jig and the underside of the blotter block may be aligned and / or engaged with one another.

[0028]

[0034] The open area of ​​jig or fixture 42 provides guidance for proper placement of the blotter paper. Blotter paper 56 has adhesive on one side that is covered by release paper 58. In the non-limiting context of the gel plate active area described above, the blotter paper has a length and width that are both slightly larger than the active area. Once the release paper is removed, the blotter paper is inserted through the opening in jig or fixture 42 and brought into contact with cushion layer 32. A slight force is applied so that the blotter paper adheres to the closed-cell cushion layer.

[0029]

[0035] The absorbent capacity of blotter paper 56 can be increased by using two or more layers of blotter paper that are bonded together with an adhesive between the layers.

[0030]

[0036] The adhesive layer or coating is a double-sided adhesive tape, one side of which is attached to the blotter paper 56. The side of the adhesive layer not attached to the blotter paper is typically covered with a release paper, which may be silicone-based. Instead of coating the entire lower surface of the blotter paper with adhesive, the lower surface of the blotter paper may alternatively have multiple sections of adhesive material, each covered with a release paper.

[0031]

[0037] After use, the blotter paper 56 can be removed from the cushion layer 32, for example, starting with one corner of the blotter paper. Another piece of blotter paper is then attached to the cushion layer as described above. Once the blotter paper contacts the gel and absorbs the liquid, the blotter paper is removed. Blotter paper is not used twice, and not with different working gel areas, because doing so could result in contamination of the working gel area or cross-contamination of the working gel area.

[0032]

[0038] Among the many benefits of using a blotter pad, one benefit is that the adhesive-backed blotter 56 can be easily removed from the blotter pad 32 so that a replacement blotter with an adhesive backing can be used for subsequent electrophoresis and / or immunofixation assays. Another benefit is that any residual adhesive on the cushion layer 32 can be easily removed and replaced if the cushion layer becomes damaged. A third benefit is that the use of adhesive prevents accidental movement of the blotter pad relative to the blotter block and the blotter paper relative to the blotter pad, thereby preventing contamination or distorted properties of the patient sample on the gel plate as a result of the adsorption step.

[0033]

[0039] Each dimension provided above is considered in the context of the working gel area and is also considered an approximate dimension to ±10%.

Claims

1. A blotter block (10), a closed-cell silicone blotter pad (32) adhesively attached to the blotter block (10) and restricted from inadvertent movement relative to the blotter block (10); blotter paper (56) adapted to be adhesively attached to the blotter pad (32) and adapted to be restricted from inadvertent movement relative to the blotter pad (32); Equipped with A blotter assembly for use in electrophoresis.

2. a fixture (42) adapted to align the blotter paper (56) with the blotter pad (32); 10. The blotter assembly of claim 1, further comprising:

3. The blotter block (10) has protrusions (28, 30) adapted to assist in aligning the blotter paper (56) with the blotter pad (32).

3. The blotter assembly of claim 1 or 2.

4. The blotter block (10) has a density of 14.3 gm / cm ２ to 17.5 gm / cm ２ applying a force to the blotter pad (32) that is between The blotter assembly according to any one of claims 1 to 3.

5. The blotter pad (32) is adapted to be removably attached to the blotter block (10); The blotter assembly according to any one of claims 1 to 4.

6. The blotter paper (56) is adapted to be removably attached to the blotter pad (32); The blotter assembly according to any one of claims 1 to 5.

7. By using the blotter assembly according to any one of claims 1 to 6, using the blotter paper without unintentionally moving the blotter paper relative to the electrophoresis gel plate; A method for adsorbing liquid from an electrophoresis gel plate.

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