Abstract:
A device and a method for casting 50 gels at once in a single gel mold are provided. Gel solution is poured into a single gel mold, solidified into a gel block, and served as monthly gel supply of electrophoresis. For each application, a gel piece is easily sliced off from the gel block and ready for sample loading.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates in general to devices and methods of gel electrophoresis, and in particular, to multiple gel preparation.  
         BACKGROUND OF THE INVENTION  
         [0002]    Gel electrophoresis is one of the most frequently utilized tools for biomedical researches and industries. In gel electrophoresis, samples are loaded into a plurality of sample wells in a gel matrix. Charged molecules in loaded samples then migrate from sample wells into gel matrix when electric field being applied. Different molecules migrate in different rate and appear as distinguishable bands in gel matrix.  
           [0003]    By placement of gel matrix, gel devices and methods can be classified into two types, vertical gel electrophoresis and horizontal gel electrophoresis. For easy gel matrix formation, sample wells of gel matrix in the two types are usually constructed differently. Vertical gel has openings from top edge while the later from planar surface. The first operation of gel electrophoresis is gel matrix formation. It takes 3 steps to prepare a single gel matrix. Step one is gel mold setup. Step two is gel solution preparation. And step three is waiting for solidification of gel solution into gel matrix. This 3-step procedure will be required for next run of gel electrophoresis because gel matrix is usually prepared individually in laboratories. The development of modern biotechnology requires projects being conducted in fast working pace within a limited time frame. Gel electrophoresis in time saving high efficiency manner is critical and highly desired. Numerous attempts have been made. Chen in U.S. Pat. No. 5,549,806 enhances efficiency by means of faster sample migration in gel matrix under higher voltage. But Chen, while achieving certain progress, fails to save time in gel casting period. Chen&#39;s device requires gel preparation individually each time when running gel electrophoresis. Anderson et al. in U.S. Pat. No. 4,169,036 teaches a device to pour multiple gels for vertical electrophoresis. But Anderson et al. fails to provide a simple way for multiple gel casting. His device requires a series of steps to assembly holders and other parts into gel mold before gel casting and a long time to clean up those parts after that. Anderson et al. further fails to use his gel for horizontal electrophoresis because sample wells are opened from top edge of gel matrix within each slab gel holder. Kirkpatrick et al. in U.S. Pat. No. 5,443,704 provides a gel container to hold commercially made pre-cast gel so that horizontal electrophoresis can be run without individual gel casting. But the majority of laboratories are prevented from accepting it in daily experiments due to its high costs, poor quality of performance, and limited gel format. Kirkpatrick et al. further fails to provide a device for researchers to pour their own multiple gels in laboratories.  
           [0004]    A simple device and method for casting multiple gels by researchers in laboratories is highly desired but remain unsolved.  
         SUMMARY OF THE INVENTION  
         [0005]    It is, therefore, an object of the invention to provide a simplified device and method to cast multiple gels by researchers in laboratories for either vertical or horizontal gel electrophoresis. The advantages of the device and method are:  
           [0006]    (1) It saves time. Electrophoresis can be performed without casting a gel matrix individually.  
           [0007]    (2) It is simple. Multiple gels are poured and stored in a single gel mold.  
           [0008]    (3) It is affordable. Low cost feature enables the majority of researchers to cast their own multiple gels in laboratories. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 shows a perspective view of a first embodiment of the invention.  
         [0010]    [0010]FIG. 2 a  is a side view of the first embodiment including poured gel solution inside.  
         [0011]    [0011]FIG. 2 b  illustrates how a gel piece is generated from solidified gel block via slicing in 45° angle.  
         [0012]    [0012]FIG. 3 a  is an illustrative diagram revealing the principle of sample well formation.  
         [0013]    [0013]FIG. 3 b  is a side view of a gel piece placed in electrophoresis chamber.  
         [0014]    [0014]FIG. 4 a  and  4   b  introduces one option of knife and guiding tool for gel slicing.  
         [0015]    [0015]FIG. 4 c  demonstrates the cooperation of the guiding tool with the gel block.  
         [0016]    [0016]FIG. 5 a  and  5   b  illustrates a second embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    For horizontal electrophoresis, it is highly desirable to pour multiple agarose gels at once and then use them for a month. One option of pouring 50 gels could be as follows:  
         [0018]    1. Setup 50 gel molds for holding gel solution.  
         [0019]    2. Install 50 combs to each gel mold for forming sample wells.  
         [0020]    3. Measure volume of gel solution 50 times.  
         [0021]    4. Pour measured gel solution 50 times into each gel mold.  
         [0022]    5. Seal each gel mold for storage. And,  
         [0023]    6. Clean up and store all those molds and combs after use.  
         [0024]    In current practice, agarose gels are still poured individually rather than 50 gels at once because its inconvenience is much greater than its achievement. Besides, it is an unnecessary burden to purchase 50 sets of the devices for most of laboratories.  
         [0025]    The essential idea of the invention is to cast up to 50 gels at once in a single gel mold.  
         [0026]    The key feature of the invention is to solidify gel solution into a single gel block. Gel pieces can be then sliced off from the gel block for electrophoresis.  
         [0027]    [0027]FIG. 1 is a perspective view of a first embodiment of the invention. A liquid container  10 , accessible from its open top, is constructed with a bottom  28  and wall  12  in rectangular shape. A plurality of teeth  30  forms multiple parallel rows. One row of teeth  30  will form one row of sample wells of a gel matrix. For example, FIG. 1 shows 6 teeth in a row and 15 rows in parallel at bottom  28 . Such teeth arrangement allows container  10  to form 15 gels at once. Each gel has 6 sample wells. All rows are parallel from each other and evenly distributed. Teeth  30  extrude from bottom  28  toward internal space  11 . The preferred material of container  10 , as well as teeth  30 , is a rigid and liquid-impermeable plastic, such as polycarbonate or acrylic. Container  10  is used as a gel mold so that its dimensions should be designed by application purpose of the gels formed inside. Container width  26  determines gel width, container height  24  determines gel length, and container length  22  determines gel thickness and how many gels to be generated. For example, to pour 15 gels in size of 6 cm gel length, 10 cm gel width, and 0.6 cm gel thickness, the parameters of container  10  will be about 10 cm in container width  26 , 4.5 cm in container height  24 , and 17 cm in container length  22 .  
         [0028]    [0028]FIGS. 2 a  and  2   b  outline the formation of multiple agarose gels. FIG. 2 a  is a side view of container  10 . Agarose gel block  20  is formed in container  10  after temperature reduction of agarose gel solution. Teeth  30  are immersed in gel solution to form sample wells at bottom side of gel block  20 . To generate a gel piece  14  for horizontal submarine gel electrophoresis, gel block  20  is sliced by knife  15  in 45° angle from top to bottom, as shown in FIG. 2 b.  Next gel piece will be sliced along dotted lines  18 . More gel pieces can be sliced in the same way through the end of gel block  20 .  
         [0029]    [0029]FIG. 3 a  is an illustrative diagram. Teeth  30  should be constructed in different angles according to different gel formats. For vertical gels, teeth  30  should be vertical on bottom  28 . But in this embodiment for horizontal gels, teeth  30  are tilted 45° towards one side, as shown in FIG. 3 a.  Remember that gel block  20  is sliced in 45° angle towards another side. As a result, a front face  11  of teeth  30  is now 90° perpendicularly formed in gel piece  14 . This 90° arrangement is critical. It will generate a vertical front wall  32  of sample wells  34  when gel piece  14  being placed horizontally in electrophoresis chamber  36 , as shown in FIG. 3 b.  Sample wells  34  are now accessible from top for sample loading, the same way as all other traditional agarose gels.  
         [0030]    [0030]FIGS. 4 a,    4   b,  and  4   c  introduce cutting tools of the first embodiment. To generate gel pieces, knife  15  is used to cut gel block  20  into slices. Knife  15  is a hand-held stainless sheet having a sharp cutting edge  13  and a handle  16 . The width of cutting edge  13  should be compatible with width of gel block  20  but slightly smaller than container width  26  in FIG. 1 so that gel block  20  can be sliced inside container  10 . To make gel slicing easy and reliable, a guiding tool  19  is utilized in the system. Guiding tool  19  controls cutting point and cutting angle of gel block  20 . There are numerous ways to design guiding tool  19 . Basically, it should have a guiding line  17  to control cutting angle and a marker  31  to identify cutting point. The correct cutting point should be set to a position where only one row of sample wells is included in one gel slice. In this embodiment, guiding tool  19  is made with two pieces of stainless sheet. They can be inserted between gel block  20  and container  10  from both sides of gel block  20 . Marker  31  contacts teeth  30  to set cutting point, as shown in FIG. 4 c.  Knife  15  is then pushed down along guiding line  17  to generate gel piece  14 .  
         [0031]    The operation of the first embodiment is as follows:  
         [0032]    1. Prepare agarose gel solution in a suitable volume.  
         [0033]    2. Pour agarose gel solution into container  10  and wait for formation of gel block via temperature reduction.  
         [0034]    3. Insert guiding tool  19  from both sides of gel block  20  to set a correct cutting point.  
         [0035]    4. Push knife  15  along guiding line  17  down in 45° angle to generate gel piece  14  from gel block  20 .  
         [0036]    5. Move guiding tool  19  to next position.  
         [0037]    6. Push knife  15  down again along guiding line  17  to slice gel block  20  into a second gel piece.  
         [0038]    7. Repeat steps 5 and 6 until reaching the end of gel block  20 .  
         [0039]    Gel block  20  can be used as a monthly gel supply of submarine electrophoresis. To prevent moisture loss of gel block  20 , container  10  can be easily sealed using a piece of plastic wrap or an airtight cover. For easy placement in laboratories, container length  22  should be less than 50 cm, which is enough to generate about 50 gels at once.  
         [0040]    [0040]FIGS. 5 a  and  5   b  illustrate a second embodiment of the invention. Container  59  has a bottom  60 , wall  62 , and open edge  70 . Teeth  74  are constructed on a plate  76  instead of container bottom  60 . Plate  76  is removable from container  59 . After solidification of gel solution, gel block  64  is tightly anchored onto plate  76 . When need to perform vertical electrophoresis, board  76  is pulled out from container  59  to a position where only one row of teeth  74  being exposed outside edge  70  of container  59 . A knife  68  is used to slice gel block  64  along edge  70  to generate gel piece  72 . The remaining portion of gel block  64 , together with plate  76 , can be moved back and stored in container  59 . Guiding tool is omitted in this embodiment because teeth  74  can be utilized to determine cutting point and edge  70  can be used as guiding line.  
         [0041]    Although the description above contains specifications, it will apparent to whose skilled in the art that a number of other variations and modifications may be made in this invention without departing from its spirit and scope. Teeth  30 , for example, can be removable from bottom  28 , wall  12  can be constructed in 45° angle with bottom  28  instead of rectangular shape, gel block  20  can be removed from container  10  and then sliced using different guiding tools for slicing. Thus, the description as set out above should not be constructed as limiting the scope of the invention but as merely providing illustration of the presently preferred embodiment of the invention.