Patent Publication Number: US-2012043212-A1

Title: Real-time fluorescent electrophoresis apparatus

Description:
1. FIELD OF THE INVENTION 
     The present invention generally relates to a real-time fluorescent electrophoresis apparatus and, more particularly, to a real-time fluorescent electrophoresis apparatus whereby the experimenter is able to observe fluorescence phenomenon from a biological sample during electrophoresis so as to trace the electrophoresis process and determine whether the electrophoresis process is to be interrupted and avoid experimental errors. 
     2. BACKGROUND OF THE INVENTION 
     Electrophoresis is usually used for analysis of biological samples (such as DNA&#39;s or proteins) to obtain molecular weights, degrees of purity or structures thereof. 
     Generally, before DNA electrophoresis, the DNA&#39;s are loaded into a gel. The gel electrophoresis technique includes agarose gel electrophoresis (AGE) for separating DNA fragments with heavier molecular weights (for example, 1 to 60000 bp) and polyacrylamide gel electrophoresis (PAGE) for separating DNA fragments with lighter molecular weights (for example, 1 to 1000 bp). 
     During gel electrophoresis, an electric field is applied to drive DNA molecules in the gel to move towards the positive electrode since the DNA molecules are negatively charged. Due to the difference in molecular weights, the moving speeds of the DNA molecules vary. Moreover, the DNA molecules are often dyed by a dying agent (such as EtBr) before they are exposed to light with a certain wavelength. The dying agent fluoresces after the light is absorbed so that the DNA molecules are observed and identified after electrophoresis. 
     As shown in  FIG. 1  for a structural diagram of a conventional electrophoresis apparatus, the electrophoresis apparatus  100  comprises an electrophoresis tank  10 , a gel  11  with a biological sample and a power supply unit  13 . The gel  11  comprises a plurality of charged molecules  111  (such as DNA molecules). The biological sample has dyed by a dying agent. The electrophoresis tank  10  comprises a platform  101 , an electrophoresis liquid  103 , a positive electrode  105  and a negative electrode  107 . The gel  11  is placed on the platform  101 . The gel  11 , the platform  101 , the positive electrode  105  and the negative electrode  107  are immersed in the electrophoresis liquid  103 . The power supply unit  13  provides DC power and is electrically connected to the positive electrode  105  and the negative electrode  107 . 
     When the power supply unit  13  provides DC power, an electric field is built across the positive electrode  105  and the negative electrode  107  so as to drive the charged molecules  111  in the gel  11  to move towards the electrodes  105 / 107  with opposite electric polarities. For example, the charged molecules  111  move towards the positive electrode  105  when they are negatively charged, while the charged molecules  111  move towards the negative electrode  107  when they are positively charged. Moreover, the moving speeds of the charged molecules  111  depend on the molecular weights thereof. In other words, the charged molecules  111  with heavier molecular weights exhibit lower speed than the charged molecules  111  with lighter molecular weights. Therefore, there exists difference in the traveling lengths of the charged molecules  111  with different molecular weights in the gel  11  after a certain period of electrophoresis time. 
     The gel  11  having experienced electrophoresis is unloaded from the electrophoresis tank  10  and is then irradiated by a light apparatus (not shown) so that the charged molecules  111  in the gel  11  fluoresce. Thereby, the charged molecules  111  can be identified by observing the positional change of the charged molecules  111 . 
     Accordingly, the biological sample in the gel  11  may undergo electrophoresis using a conventional electrophoresis apparatus  100 . However, during the electrophoresis process, the moving speeds of the charged molecules  111  of the biological sample under an applied electric field may vary, which results in different electrophoresis time periods in the same gel  11 . Presently, there is no method that is capable of precisely calculating the moving speeds of the charged molecules  111  during electrophoresis. If the biological sample to undergo electrophoresis has experienced the experiment, the time required for electrophoresis of the biological sample can be empirically estimated. On the contrary, if the biological sample to undergo electrophoresis has not experienced the experiment, the time required for electrophoresis can be obtained by trial and error. In other words, after each electrophoresis process, the experimenter has to check whether the electrophoresis result is satisfactory by using a light apparatus. The electrophoresis time has to be adjusted if the electrophoresis result is not satisfactory. Therefore, the charged molecules  111  with different molecular weights in the gel  11  can be identified so as to avoid that the electrophoresis time is too short unable to separate the charged molecules  111  with different molecular weights in the gel  11  and that the electrophoresis time is so long that all the charged molecules  111  with different molecular weights drift from the gel  11  into the electrophoresis liquid  103 . 
     In view of the above, the present invention provides a real-time fluorescent electrophoresis apparatus, in which the experimenter is able to observe fluorescence phenomenon from the biological sample during electrophoresis so as to trace the electrophoresis process and determine whether the electrophoresis process is to be interrupted and avoid experimental errors. 
     SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide a real-time fluorescent electrophoresis apparatus, whereby the experimenter is able to observe fluorescence phenomenon from a biological sample during electrophoresis so as to trace the electrophoresis process and determine whether the electrophoresis process is to be interrupted and avoid experimental errors. 
     It is another object of the present invention to provide a real-time fluorescent electrophoresis apparatus, in which at least one anti-fog element is disposed on one surface or one side of the filter so as to prevent the vapor of the electrophoresis liquid being condensed on the filter to hinder the experimenter observing the fluorescence phenomenon from the biological sample. 
     It is still another object of the present invention to provide a real-time fluorescent electrophoresis apparatus, in which an air flow is conducted so as to carry away the vapor inside the real-time fluorescent electrophoresis apparatus and prevent the vapor being condensed on the filter to hinder the experimenter observing the fluorescence phenomenon from the biological sample. 
     To achieve the above objects, the present invention provides an real-time fluorescent electrophoresis apparatus, comprising: an electrophoresis tank comprising a platform, an electrophoresis liquid, a positive electrode and a negative electrode, the platform carrying a gel with a biological sample, the gel comprising a plurality of charged molecules of the biological sample, and the gel, the platform, the positive electrode and the negative electrode being immersed in the electrophoresis liquid; a lid covering the electrophoresis tank and comprising a filter disposed above the gel and at least one luminous element disposed on at least one side of the filter to irradiate the gel so that the biological sample in the gel is excited to fluoresce; and a power supply unit electrically connected to the positive electrode, the negative electrode and the luminous element so that an electric field is built across the positive electrode and the negative electrode to drive the charged molecules to move in the gel and provide the luminous element with electricity to luminesce. 
     The present invention further provides a real-time fluorescent electrophoresis apparatus, comprising: an electrophoresis tank comprising a platform, an electrophoresis liquid, a positive electrode and a negative electrode, the platform being transparent and carrying a gel with a biological sample, the gel comprising a plurality of charged molecules of the biological sample, the platform comprising at least one luminous element therein to irradiate the gel on the platform so that the biological sample in the gel is excited to fluoresce, and the gel, the platform, the positive electrode and the negative electrode being immersed in the electrophoresis liquid; a lid covering the electrophoresis tank and comprising a filter disposed above the gel; and a power supply unit electrically connected to the positive electrode, the negative electrode and the luminous element so that an electric field is built across the positive electrode and the negative electrode to drive the charged molecules to move in the gel and provide the luminous element with electricity to luminesce. 
     The present invention another provides a real-time fluorescent electrophoresis apparatus, comprising: an electrophoresis tank comprising a platform, an electrophoresis liquid, a positive electrode and a negative electrode, the platform being transparent and carrying a gel with a biological sample, the gel comprising a plurality of charged molecules of the biological sample, the platform comprising at least one luminous element therein to irradiate the gel on the platform so that the biological sample in the gel is excited to fluoresce, and the gel, the platform, the positive electrode and the negative electrode being immersed in the electrophoresis liquid; a base comprising a bottom portion and a vertical portion, the electrophoresis tank disposed on the bottom portion, the bottom portion comprising an inlet fan with a air inlet and the vertical portion comprising an aperture to define a air flow path between the air inlet and the aperture so that a air flow is driven by the inlet fan into the air inlet to pass the air flow path and is discharged from the aperture; a filter disposed above the gel and fixedly on the vertical portion of the base so that a gap is defined between the filter and the electrophoresis tank; a air outlet disposed opposite to the gap so that the air flow discharged from the aperture passes through the gap to carry away the vapor on the filter out of the air outlet; and a power supply unit electrically connected to the positive electrode, the negative electrode, the luminous element and the inlet fan so as to build up an electric field across the positive electrode and the negative electrode to move the charged molecules in the gel and provide the luminous element and the inlet fan with electricity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects and spirits of the embodiments of the present invention will be readily understood by the accompanying drawings and detailed descriptions, wherein: 
         FIG. 1  is a structural diagram of a conventional electrophoresis apparatus; 
         FIG. 2  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to one preferred embodiment of the present invention; 
         FIG. 3  is a top view of a real-time fluorescent electrophoresis apparatus according to the present invention; 
         FIG. 4  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 5  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 6  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 7  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 8  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 9  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 10  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 11  is a stereogram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 12  is an upside-down stereogram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 13  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 14  is a stereogram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 15  is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 16  is a stereogram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; 
         FIG. 17  is an upside-down stereogram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention; and 
         FIG. 18  is a perspective view of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention can be exemplified but not limited by various embodiments as described hereinafter. 
     Please refer to  FIG. 2  and  FIG. 3  for a structural diagram and a top view of a real-time fluorescent electrophoresis apparatus according to one preferred embodiment of the present invention. The real-time fluorescent electrophoresis apparatus  20  of the present embodiment comprises an electrophoresis tank  20 , a lid  30  and a power supply unit  23 . 
     The electrophoresis tank  20  comprises a platform  201 , an electrophoresis liquid  203 , a positive electrode  205  and a negative electrode  207 . The platform  201  carries a gel  21  with a biological sample (such as protein, DNA, RNA, etc). The gel  21  comprises a plurality of charged molecules  211  of the biological sample that has dyed by a dying agent. The gel  21 , the platform  201 , the positive electrode  205  and the negative electrode  207  are immersed in the electrophoresis liquid  203 . The lid  30  covers and surrounds the electrophoresis tank  20 . The lid  30  comprises a filter  31  and at least one luminous element  33 . The filter  31  is an amber filter disposed above the gel  21 . The luminous element  33  is inclinedly disposed on at least one side of the filter  31  to irradiate the gel  21 . The irradiation zone of the luminous element  33  covers the gel  21  to excite the biological sample in the gel  21  to fluoresce. The power supply unit  23  is a DC power supply unit and is electrically connected to the positive electrode  205 , the negative electrode  207  and the luminous element  33  to provide the positive electrode  205 , the negative electrode  207  and the luminous element  33  with electricity. 
     During electrophoresis, the power supply unit  23  provides electricity so that an electric field is built across the positive electrode  205  and the negative electrode  207  so as to drive the charged molecules  211  in the gel  21  to move towards the electrodes  205 / 207  with opposite electric polarities. For example, the charged molecules  211  move towards the positive electrode  205  when they are negatively charged, while the charged molecules  211  move towards the negative electrode  207  when they are positively charged. Meanwhile, the luminous element  33  luminesces to irradiate the gel  21  to excite the biological sample in the gel  21  to fluoresce. Moreover, when the experimenter observes the fluorescence phenomenon from the charged molecules  211  of the biological sample through the filter  31 , the filter  31  is able to filter out the light from the luminous element  33  and allows only the fluorescence from the biological sample to pass therethrough. 
     Accordingly, the experimenter is able to observe the positional change of the charged molecules  211  of the biological sample in the gel  21  in real time to trace the electrophoresis process. Therefore, the experimenter can determine whether the electrophoresis process is to be interrupted and avoid experimental errors according to the positions of the charged molecules  211  in the gel  21 . 
     In the present invention, the luminous element  33  is a light-emitting diode capable of irradiating the gel  21  by emitting monochromatic light such as blue, ultraviolet or green light. Moreover, the luminous element  33  is inclinedly disposed with an adjustable inclined angle corresponding to the position of the gel  21 . The number of luminous elements can be larger than one so as to achieve improved irradiation according to practical demands. 
     Furthermore, during electrophoresis, the electrophoresis liquid  203  is heated up by the electric field to cause vapor to be condensed on the filter  31 , which hinders the experimenter observing the fluorescence phenomenon from the biological sample. Therefore, in the present invention, at least one anti-fog element  35  may be disposed on one surface (for example, the bottom surface) of the filter  31 . The anti-fog element  35  comprises at least one thermal wire and is electrically connected to the power supply unit  23  to provide electricity. When the anti-fog element  35  is turned on, the anti-fog element  35  is heated up to keep the filter  31  at a temperature higher than the room temperature so as to prevent the vapor of the electrophoresis liquid  203  being condensed on the filter  31  to hinder the experimenter observing the fluorescence phenomenon from the biological sample. 
     Please refer to  FIG. 4 , which is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention. In the present embodiment, the electrophoresis tank  20  and the lid  30  in the real-time fluorescent electrophoresis apparatus  301  may be powered by respective power supply elements. For example, the power supply unit  23  may comprise a first power supply element  231  and a second power supply element  233 . The first power supply element  231  provides the positive electrode  205  and the negative electrode  207  with electricity, while the second power supply element  233  provides the luminous element  33  and the anti-fog element  35  with electricity. The second power supply element  233  is a power control element capable of determining whether the luminous element  33  is to be turned on and whether the anti-fog element  35  provides thermal energy. 
     Please refer to  FIG. 5 , which is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention. In addition to the embodiment shown in  FIG. 2  where the lid  30  of the real-time fluorescent electrophoresis apparatus  300  is disposed surrounding the electrophoresis tank  20 , the lid  30  of the real-time fluorescent electrophoresis apparatus  302  may be fixedly constructed on the electrophoresis tank  20 , as shown in  FIG. 5 . 
     Please refer to  FIG. 6 , which is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention. In addition to the foregoing embodiments wherein the luminous element  33  of the real-time fluorescent electrophoresis apparatus  300 / 301 / 302  is disposed on one side of the filter  31  of the lid  30 , the luminous element  33  of the real-time fluorescent electrophoresis apparatus  303  of the present embodiment may also be disposed inside the platform  202  of the electrophoresis tank  20 , as shown in  FIG. 6 . 
     The platform  202  of the present embodiment is a transparent platform capable of carrying a gel  21  with biological samples thereon. At least one luminous element  33  is inclinedly disposed on one side inside the platform  202  to upward irradiate the gel  21  on the platform  202 . The biological sample in the gel  21  is excited to fluoresce. Thereby, the experimenter is able to observe the positional change of the charged molecules  211  of the biological sample in the gel  21  through the filter  31  to trace the electrophoresis process in real time. Moreover, the real-time fluorescent electrophoresis apparatus  303  of the present embodiment is similarly to the structure of the embodiment as shown in  FIG. 2  except the luminous element  33 , and thus description thereof is not to be repeated herein. 
     Please refer to  FIG. 7 , which is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention. The real-time fluorescent electrophoresis apparatus  304  of the present embodiment is similar to the real-time fluorescent electrophoresis apparatus  303  of the embodiment as shown in  FIG. 6  except that the lid  30  of the real-time fluorescent electrophoresis apparatus  304  is fixedly constructed on the electrophoresis tank  20  instead of being disposed surrounding the real-time fluorescent electrophoresis apparatus  303 . 
     Please refer to  FIG. 8 , which is a structural diagram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention. Compared to the real-time fluorescent electrophoresis apparatus  304  of the embodiment in  FIG. 7  where a thermal wire is disposed on one surface of the filter  31  as an anti-fog element  35 , an outlet fan may also be used as an anti-fog element  361  of the real-time fluorescent electrophoresis apparatus  305  of the present embodiment. The anti-fog element  361  is disposed on one side of the filter  31  so as to deflate the electrophoresis tank  20  and prevent the vapor of the electrophoresis liquid  203  being condensed on the filter  31 . 
     Alternatively, as shown in  FIG. 9 , another anti-fog element  363  may be provided on another side of the filter  31 . An inlet fan may be used as the anti-fog element  363  so as to inflate the real-time fluorescent electrophoresis apparatus  305 . By the use of the inlet fan  363  and the outlet fan  361 , an air flow is conducted inside the real-time fluorescent electrophoresis apparatus  305  so as to carry away the vapor inside the real-time fluorescent electrophoresis apparatus  305  and prevent the vapor being condensed on the filter  31 . 
     Moreover, in addition to the air flow for carrying away the vapor inside the electrophoresis tank  20 , the present invention further provides other embodiments, as shown in  FIG. 10 ,  FIG. 11  and  FIG. 12  for a structural diagram, a stereogram and an upside-down stereogram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention. The real-time fluorescent electrophoresis apparatus  306  of the present embodiment comprises an electrophoresis tank  20 , a base  50  and a power supply unit  23 . 
     In the present embodiment, the electrophoresis tank  20  comprises a platform  202 , an electrophoresis liquid  203 , a positive electrode  205  and a negative electrode  207 . The platform  202  is transparent and is capable of carrying a gel  21  with a biological sample (such as protein, DNA, RNA, etc). The gel  21  comprises a plurality of charged molecules  211  of the biological sample that has dyed by a dying agent. The gel  21 , the platform  202 , the positive electrode  205  and the negative electrode  207  are immersed in the electrophoresis liquid  203 . At least one luminous element  33  is inclinedly disposed on at least one side inside the platform  202  to upward irradiate the gel  21  on the platform  202 . The biological sample in the gel  21  is excited to fluoresce. 
     The base  50  is hollow and comprises a bottom portion  501  and a vertical portion  503 . The electrophoresis tank  20  is disposed on the bottom portion  501 , which is provided with an inlet fan  51  having an air inlet  511 . The vertical portion  503  is provided with an aperture  55  so that an air flow path  53  is defined between the air inlet  511  and the aperture  55 . A filter  31  is disposed above the gel  21  and is fixedly disposed on the vertical portion  503  of the base  50  by contacting of a connecting portion  311 . A gap  208  is defined between the filter  31  and the electrophoresis tank  20  and an air outlet  209  is provided opposite to the gap  208 . The power supply unit  23  may be a DC power supply unit and is electrically connected to the positive electrode  205 , the negative electrode  207 , the luminous element  33  and the inlet fan  51  so as to provide the positive electrode  205 , the negative electrode  207 , the luminous element  33  and the inlet fan  51  with electricity. 
     During electrophoresis, the electrophoresis liquid  203  in the electrophoresis tank  20  is heated up by the electric field across the positive electrode  205  and the negative electrode  207  to generate the vapor onto the filter  31 . Meanwhile, an air flow  59  is driven by the inlet fan  51  into the air inlet  511  to pass the air flow path  53  and is discharged from the aperture  55 . The discharged air flow  59  then passes through the gap  208  to carry away the vapor on the filter  31  out of the air outlet  209 . Thereby, the vapor is prevented being condensed on the filter  31  to hinder the experimenter observing the fluorescence phenomenon from the biological sample. 
     In the present embodiment, the air inlet  511  is provided on the bottom surface of the bottom portion  501 . A plurality of pillars  52  may be further provided on the bottom surface of the bottom portion  501  so that there is more space between the air inlet  511  and a planar surface for the inlet fan  51  to introduce the air flow  59  into the air inlet  511  when the real-time fluorescent electrophoresis apparatus  306  is placed on the planar surface. 
     As shown in  FIG. 13 , the air inlet  511  of the real-time fluorescent electrophoresis apparatus  306  may also be disposed on one lateral side of the bottom portion  501 . In this case, the pillars  52  are not required. 
     As shown in  FIG. 14 , to further enhance the air flow  59 , the real-time fluorescent electrophoresis apparatus  306  may further comprise a pair of side plates  57  disposed on both sides of the base  50 . As a result, the discharged air flow  59  from the aperture  55  will not be weakened due to dissipation from the two sides of the base  50 . Thereby, the air flow  59  with constant strength is able to carry away the vapor on the filter  31  out of the air outlet  209 . 
     Please refer to  FIG. 15 ,  FIG. 16  and  FIG. 17  for a structural diagram, a stereogram and an upside-down stereogram of a real-time fluorescent electrophoresis apparatus according to another embodiment of the present invention. The real-time fluorescent electrophoresis apparatus  306  of the present embodiment comprises an electrophoresis tank  20 , a base  50  and a power supply unit  23 . The real-time fluorescent electrophoresis apparatus  307  of the present embodiment is similar to the real-time fluorescent electrophoresis apparatus  306  of the previous embodiment except that the filter  31  of the real-time fluorescent electrophoresis apparatus  307  may also be disposed on a side frame  70  instead of being fixedly disposed on the vertical portion  503  of the base  50  by contacting of a connecting portion  311  of the real-time fluorescent electrophoresis apparatus  306  of the previous embodiment. However, the filter  31  of the real-time fluorescent electrophoresis apparatus  307  of present embodiment may also be disposed on the side frame  70  that is fixedly disposed on the vertical portion  503  of the base  50 . 
     Moreover, in the present embodiment, the side frame  70  and the base  50  may be made of the same material so that the two can be tightly adhered to each other. Thereby, the filter  31  is fixedly disposed on the base  50  without risk of falling down. 
     As shown in  FIG. 18 , the real-time fluorescent electrophoresis apparatus  307  may also comprise a pair of side plates  57  disposed on both sides of the base  50  so that the air flow  59  with constant strength is able to carry away the vapor on the filter  31  out of the air outlet  209 . 
     Although this invention has disclosed and illustrated with reference to particular embodiments, the principles involved are susceptible for use in numerous other embodiments that will be apparent to persons skilled in the art. This invention is, therefore, to be limited only as indicated by the scope of the appended claims.