Water-absorbing pad for electrophoresis

Abstract

An electrophoresis wicking assembly comprising a block and a closed cell silicone wicking pad adhered to the block and restrained from unintended movement relative to the block.

Description

Technical Field

[0001] Electrophoresis is one of the most common methods for separating proteins, nucleotides, and other biomolecules. Methods vary depending on the medium used (e.g., agarose, acrylamide, cellulose, capillary) and the chemical interactions employed in the process (e.g., capillary regions, immunofixation, immunodepletion, etc.). While there are many different types of electrophoresis, all electrophoresis separates a sample into its individual components by applying a voltage to the medium in which the sample is placed. The electrophoretic mobility of molecules depends on the type of medium used, the pH value, and the characteristics of each molecule, such as size, shape, charge, and interactions with other molecules in the chosen medium. Background Technology

[0002] In the simplest form of electrophoresis, macromolecules in a sample are separated on a gel or other medium. A staining agent is applied, revealing the sample separation profile as bands representing each different component in the sample. The density and width of these bands are measured and used as quantitative and / or qualitative measurements of the various macromolecules in the sample. In some cases, a single band may contain signals from several similar but different macromolecules. Further identification and characterization of the macromolecules generating signals within each band can be achieved by removing selected bands and performing further diagnostic tests.

[0003] Serum protein electrophoresis (SPE) and immunofixation electrophoresis (IFE) are among the oldest and most widely used clinical diagnostic tools today. Typically, SPE and / or IFE can be performed on blood samples from a patient, with little or no sample preparation. Samples can be placed directly into the grooves of an agarose gel, which can be run for an appropriate time, stained with Coomassie Brilliant Blue or other common protein staining agents, and the protein separation profiles containing characteristic bands of serum proteins can be easily observed. In some cases, the sample may be diluted or treated first to avoid coagulation, but in others preparation is not necessary. The separation patterns produced by SPE depend on the proportions of two main proteins: albumin and globulin, both present in the sample. Albumin and globulin bands contain signals from many similar but distinct proteins.

[0004] The gamma region of a plasma cell (SPE) is primarily composed of immunoglobulins, also known as antibodies. Plasma cells produce immunoglobulins (also called gamma globulins), which consist of heavy chains (IgG, IgA, IgM, IgD, or IgE) linked together with light chains (κ or λ). Patient samples can be placed in multiple regions or lanes on an agarose gel plate. After an electrophoresis step, different antisera deposit in different lanes, and an antiserum-antibody reaction occurs, indicating the presence and quantity of antibodies in the sample. The reaction can be observed using staining agents.

[0005] An inherent requirement in the above process is the removal of excess liquid. It should be understood that the term "liquid" in this document refers individually and collectively to patient samples, including the components of those samples, substances used to dilute the samples, staining agents, antiserum, and detergents, as well as substances used to remove excess and / or unreacted samples, their components, staining agents, and detergents. The presence of excess "liquid" can interfere with the qualitative and quantitative analysis of results. Furthermore, after testing, excess liquid must be removed from the electrophoresis and / or IFE equipment for subsequent testing. For example, increased removal of excess liquid in the electrophoresis and immunofixation steps results in less residual liquid needing to be removed between consecutive tests.

[0006] Historically, absorbent paper was used to absorb and thus remove excess liquid from electrophoresis gel plates. Absorbent paper (or more accurately, absorbent sheet) is sometimes referred to as absorbent paper, superabsorbent paper, or other materials that absorb excess liquid from another surface. Cotton is frequently used to make absorbent paper.

[0007] In existing electrophoresis procedures, absorbent paper strips are manually placed on the agarose gel and held in situ for a desired duration to absorb excess liquid, after which they are manually removed. Furthermore, to enhance liquid absorption, some systems incorporate additional weight on the absorbent paper in the form of physical blocks. These blocks offer several advantages, such as maintaining contact between the absorbent paper and the gel to increase the absorption rate, increasing the amount absorbed, preventing the absorbent paper from curling off the gel surface, and distributing a more even downward force across the absorbent paper due to its weight. Examples of the use of gel blocks and absorbent paper are known, for example, in the TITAN® GEL immunofixation procedure and SPIFE® IgG procedure sold by Helena Laboratories, Beaumont, Texas, USA, the applicant for the improved absorbent pad for electrophoresis of this invention.

[0008] The use of absorbent paper and prior art blocks has several limitations, including but not limited to (a) difficulty in removing the absorbent paper after use, as the absorbent paper sheets may adhere to the block; (b) undesirable movement between the absorbent paper and the block when the block is placed on absorbent paper pre-placed on the gel; and (c) uneven weight distribution of the block on the absorbent paper, resulting in uneven weight distribution of the block and absorbent paper on the gel. The use of prior art absorbent paper is limited due to the manual nature of the absorbent process. Summary of the Invention

[0009] The improved absorbent pad for electrophoresis is a multi-part assembly that allows the pad to be secured or attached to the absorbent block, the absorbent paper to be secured or attached to the pad, and facilitates weight distribution on the absorbent paper and gel, thereby avoiding unwanted movement between the absorbent paper and the absorbent pad and between the absorbent paper and the gel, and allowing the absorbent paper to be easily and completely removed from the pad after the absorbent paper step is completed.

[0010] The improved electrophoresis absorbent pad also includes a removable adhesive backing fabric, allowing the pad to be removed from the absorbent block when necessary, and a replacement absorbent pad to be attached to the block. Since absorbent paper is typically used only once, the improved electrophoresis absorbent pad can be easily removed and replaced with dry absorbent paper, which features improved absorbent paper including an adhesive backing fabric, so that the absorbent paper remains in place to prevent accidental movement. Attached Figure Description

[0011] The benefits of the improved absorbent block and pad for electrophoresis described above, as well as the improved absorbent paper, and other benefits and advantages obtainable from using the absorbent block and pad, will become more apparent after reading the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings,

[0012] Figure 1 A perspective view of the absorbent block as seen from the top;

[0013] Figure 2 For viewing from the bottom Figure 1 A perspective view of the absorbent block;

[0014] Figure 3 For including absorbent pads Figure 1 Another perspective view of the absorbent block;

[0015] Figure 4 Perspective view of the absorbent pad;

[0016] Figure 5 Exploded perspective view of absorbent blocks and absorbent pads; and

[0017] Figure 6 An exploded perspective view of absorbent blocks, absorbent pads, absorbent paper, and fixtures or clamps for properly positioning absorbent paper on absorbent pads. Detailed Implementation

[0018] In the following description and accompanying drawings, the various length and width dimensions are for illustrative purposes only. These dimensions are provided relative to the “gel area” on the electrophoresis gel, in which the patient sample is deposited, electrophoresis is performed, reagents are deposited, and staining agents are deposited. These dimensions are also illustrative and not limiting, to compensate for the size of the equipment used in the electrophoresis system. Thus, as a non-limiting example, when using the SPIFE Nexus device manufactured by Helena Laboratories, Inc., Beaumont, Texas (USA), a typical gel area for a patient has a rectangular configuration, approximately 11.43 × 12.7 cm (4.5 × 5.0 inches). The length and width of absorbent paper must be greater than the gel area. The length and width of absorbent blocks and absorbent pads must be greater than the absorbent paper. Again, the use of a rectangular gel area is for illustrative purposes only.

[0019] Therefore, the improved absorbent block 10 is shown with a generally rectangular configuration, having two opposing short sides 12, 14 and two opposing long sides 16, 18. The length and width of the absorbent block are approximately 13.34 × 14.99 cm (5.25 × 5.90 inches), which is larger than the patient sample gel area in both length and width.

[0020] The absorbent pad 10 has an upper surface 20 and a lower surface 22. As previously mentioned, the precise dimensions can vary depending on the nature of the machine used in the electrophoresis system. The dimensions, shapes, proportions, and materials described in this and the following paragraphs should be understood as illustrative rather than limiting. The upper surface 20 of the absorbent pad may include protrusions 24, 26 extending upward on opposite sides 16, 18 of the pad and positioned closer to the shorter side 12. These protrusions facilitate the use of a machine, such as the aforementioned SPIFE Nexus, to lift and move the absorbent pad. Other lifting and manipulation methods and systems can be used, such as, but not limited to, systems using magnetic coupling. Importantly, the absorbent pad 10 can be inverted for removing used absorbent paper and replacing it with new absorbent paper, as will be described below, and for moving the substrate between various gel areas on the electrophoresis plate so that multiple samples can be sequentially blotted dry, each sample blotted dry with new (i.e., unused) absorbent paper to avoid contamination between samples from different patients.

[0021] The lower side 22 of the absorbent block 10 includes elongated protrusions 28 and 30 that are parallel to each other. Each protrusion extends substantially the entire length of the block from the first end 12 to the second end 14 and is adjacent to the sides 16 and 18, respectively. The protrusions facilitate the proper alignment of the absorbent pad and absorbent paper, which will be explained below.

[0022] In the non-limiting example described, the gel plate contact area of ​​the underside 22 of the absorbent block 10 (excluding the area surrounded by the protrusions 28, 30) is approximately 12.7 x 13.2 cm (5.0 x 5.2 inches).

[0023] Preferably, the absorbent block may be made of stainless steel and weigh approximately 3.18 kg (7 lbs). This weight helps the absorbent paper's natural wicking properties, allowing it to absorb excess liquid on the agarose (or other) gel without damaging the patient sample and / or the gel plate surface.

[0024] More typically, for approximately 199.84 cm 2 The contact area of ​​the gel plate was approximately 13.34 × 14.99 cm, and the effective weight (force) of the gel block on the gel plate was 15.89 gm / cm. 2 .

[0025] Next reference Figure 3 and Figure 4 The absorbent pad 32 also includes a thin cushioning foam layer, which preferably has the same overall configuration or shape as the gel contact area of ​​the underside 22 of the absorbent block 10, for example, rectangular. The length and width of the foam layer are preferably slightly smaller than the length and width of the underside of the block, for example, 13.21 × 12.7 cm (5.0 × 5.2 inches), although larger than the length and width of the patient area of ​​the gel plate. The foam layer is preferably a closed-cell silicone rubber foam with a thickness of approximately 0.48 cm (0.1875 inches). The closed-cell foam layer preferably has an acrylic adhesive backing on one side, and... Figure 4 In the diagram, a conventional release paper 34 is shown covering the absorbent pad 32. The release paper is removed when it is necessary to attach the absorbent pad 32 to the underside of the absorbent block 10 between the protrusions 28 and 30.

[0026] If necessary, the foam cushioning layer can be double-layered, with one layer in contact with the absorbent block 10. In this case, the layer in contact with the underside of the absorbent block 10 can be PVC (polyvinyl chloride) foam.

[0027] Importantly, since the purpose of the absorbent pad 32 is to apply appropriate pressure to the patient's gel area on the gel plate, the silicone rubber layer preferably has the same or less hardness as the electrophoresis gel and is used to help distribute the weight of the absorbent block 10 on the gel and balance the pressure (force) on the gel by conforming to the surface profile of the gel, thereby helping to provide approximately uniform absorbency to the gel plate and protecting the gel plate from damage. The absorbent pad 32 is preferably corrosion-resistant. When the absorbent pad 32 wears or is damaged, it can be removed from the underside of the absorbent block 10, removing any residual adhesive from the absorbent block 10, and a replacement cushioning layer can be attached to the underside 22 of the absorbent block 10.

[0028] Another advantage of the corrosion-resistant absorbent pad 32 is that it protects the layer from damage when attaching and removing absorbent paper, as described below.

[0029] Figure 5 An exploded perspective view of the absorbent block and absorbent pad shows the absorbent pad 32 positioned below the absorbent block 22, typically between the protrusions 28 and 30.

[0030] Figure 6 An exploded perspective view of the application of absorbent paper to absorbent block 10. A rectangular clamp or fixing device 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 clamp or fixing device include recesses 52, 54 to be aligned with protrusions 28, 30 relative to the underside of absorbent block 10. Alternatively, if desired, the clamp or fixing device may include protrusions, and the underside 22 of block 10 may include recesses to receive these protrusions.

[0031] Therefore, by removing any release paper from the underside of the absorbent pad 32, the buffer layer is attached to the underside 22 of the absorbent block 10 and held in place by the adhesive portion of the buffer layer.

[0032] Before or after the absorbent pad 32 is applied to the underside of the absorbent block 10, the clamp and the underside of the absorbent block can be aligned and / or engaged with each other.

[0033] The open area of ​​the clamp or fixation device 42 provides guidance for the proper positioning of the absorbent paper. The absorbent paper 56 includes an adhesive covered on one side by release paper 58. In the non-limiting context of the gel plate patient area as described above, the absorbent paper is slightly larger than the patient area in both length and width. When removing the release paper, the absorbent paper is inserted through the opening in the clamp or fixation device 42 and positioned to contact the absorbent pad 32. A slight force is applied to adhere the absorbent paper to the closed-cell buffer layer.

[0034] The absorbency of absorbent paper 56 can be improved by using two or more layers of absorbent paper bonded together by interlayer adhesive.

[0035] The adhesive layer or coating may be double-sided tape, with one side attached to absorbent paper 56. The side of the adhesive layer not attached to the absorbent paper is typically covered with a release liner, which may be silicone-based. Alternatively, instead of coating the entire underside of the absorbent paper with adhesive, the underside of the absorbent paper may have several sections of adhesive material, each section covered with release liner.

[0036] After use, absorbent paper 56 can be removed from absorbent pad 32, for example, starting from one corner of the absorbent paper. Then, as previously described, another absorbent paper is attached to the buffer layer. Once the absorbent paper has come into contact with the gel and absorbed the liquid, the absorbent paper is removed. It will not be reused or used on different patient gel areas, as any such use could lead to contamination of the patient gel area or cross-contamination between patient gel areas.

[0037] One of the many advantages of using an absorbent pad is that the absorbent paper 56 with the adhesive backing can be easily removed from the absorbent pad 32, allowing replacement absorbent paper with the adhesive backing to be used for subsequent electrophoresis and / or immunofixation tests. Another advantage is that any adhesive residue on the absorbent pad 32 can be easily removed, and the buffer layer can be easily removed and replaced if damaged. A third advantage is that, by using the adhesive, the absorbent pad will not move accidentally relative to the absorbent block, nor will the absorbent paper move accidentally relative to the absorbent pad; therefore, patient samples on the gel plate will not be contaminated or deformed due to the absorbent step.

[0038] Each of the above dimensions should be considered in the context of the patient's gel area, and also in the fact that the dimension is approximately ±10% of the original size.

Claims

1. A water-absorbing assembly for electrophoresis, comprising an absorbent block (10) and an absorbent pad (32), characterized in that, The absorbent pad is made of closed-cell silicone rubber foam. The absorbent pad is adhered to the absorbent block by an adhesive and its accidental movement relative to the absorbent block is restricted. It also includes absorbent paper (56), which is adhered to the absorbent pad (32) by an adhesive and its accidental movement relative to the absorbent pad is restricted.

2. The absorbent assembly according to claim 1 further includes a fixing device (42) adapted to align the absorbent paper (56) with respect to the absorbent pad (32).

3. The water-absorbing component according to claim 2, wherein, The absorbent block (10) includes protrusions (28, 30) adapted to help align the absorbent paper (56) with respect to the absorbent pad (32).

4. The water-absorbing component according to claim 3, wherein, The force exerted by the absorbent block (10) on the absorbent pad (32) is 14.3 gm / cm. 2 Up to 17.5 gm / cm 2 between.

5. The water-absorbing component according to claim 4, wherein, The absorbent pad (32) is adapted to be detachably connected to the absorbent block (10).

6. The water-absorbing component according to claim 5, wherein, The absorbent paper (56) is adapted to be detachably attached to the absorbent pad (32).

7. A method for absorbing liquid from an electrophoresis gel plate using absorbent paper, wherein the absorbent paper does not move accidentally relative to the gel plate by using the absorbent assembly of any one of claims 1-6.

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