Gel Electrophoresis Integrated System (GelIS)





Introduction: Gel Electrophoresis Integrated System (GelIS)

The Gel Electrophoresis Integrated System is a way to build your own gel electrophoresis system.  Gel electrophoresis generally has three steps:
  1. Casting the gel
  2. Applying an electric field across the gel
  3. Viewing the results
This system allows you to do all three in a compact form factor.  The gel is cast directly into the tray, which is then loaded with DNA samples and inserted into the bottom chamber of the box, which can be sen in picture 2.  When powered on with the top button in picture 1, the voltage display will indicate a voltage across the terminals.  Once this happens, the DNA fragments will migrate across the gel, and gasses will start to form at the electrodes (image 5).  Condensation will start to cloud the bottom chamber.  However, the gel can be moved to the top chamber at any time and illuminated with the blue LED panel, allowing you to see the progress, or to view final results.

This system has been specially constructed with the scientists ease of use in mind.  The trays are very cheap to build, which allows users to own several.  This means they can be pre-cast in parallel and stored in a refrigerator, saving time.  The system is also very compact, at only 5.5"x5.5", saving bench space.  And the whole system is inexpensive, which means it is perfect for teaching.  I intend to sell a kit for around $200 for the entire package, while similar commercial systems sell just the box (no power supply or illuminator) for $600.

Read more about the development on my blog!

Beta test the kit here!!!  It can be expensive and difficult to get all the parts, but if you want you can just buy them!

Step 1: Gather the Materials

To assemble GelIS from scratch you will need to laser cut parts and get all the materials on the bill of materials.

Laser Cut Plastic:
  • Top and Bottom plates from .118" orange acrylic (orange, picture 1)
  • Shelf from .118" clear acrylic (clear, picture 1)
  • Safety walls from .118" clear acrylic (clear, picture 2)
  • Gel box walls from .177" clear acrylic (picture 3)
  • Gel box floor from .118" white translucent acrylic (picture 3)
  • 2x Switches
  • 1x 2.1x5.5mm female barrel connector to terminal block
  • 1x Voltmeter (0-99v readout, 12v power)
  • 1x blue LED panel
  • 1x 12-30v input 60-100v output high voltage boost converter
  • 1x 12v power supply with male 2.1x5.5mm barrel connector out
  • 6x   2" long black oxide 4-40 bolt
  • 2x   7/16" long 18-8 stainless steel pan head 4-40 bolt
  • 2x   3/8" long 18-8 stainless steel truss head 4-40 bolt
  • 8x   1" long nylon pan head 4-40 bolt
  • 10x  black nylon acorn nut 4-40 thread
  • 10x  black nylon hex nut 4-40 thread
  • 10x  stainless steel hex nut 4-40 thread
  • 16x  316 stainless steel washer
  • 2x   1/8" long 1/4" OD 6/6 nylon spacer for 4-40 screw
  • 12x .75" long 1/4" OD 6/6 nylon spacer for 4-40 screw
  • 10"  .016" diameter 316 stainless steel wire

Step 2: Top Plate Electronics Assembly

Using two 1" long 4-40 nylon bolts and two 4-40 nylon hex nuts fasten the voltmeter to the top panel.  Then use the two round nuts that came with the switches to fasten the switches to the top panel.  When you are done, it should look like this picture.

Step 3: Bottom Plate Electronics Assembly

First, remove the backing from the LED panel and stick it in the middle of the bottom half of the bottom plate.  This should be on the side near the semicircle cutout.  Make sure the cables point in the same direction as the picture.

Then add the binding posts in the upper right hand part of the image.  They are 4-40 nylon screws attached to the plate with 4-40 nylon hex nuts.

Attach the high voltage boost converter to the upper left corner.  Make sure the terminal blocks are pointed towards the binding posts you just added.  It should be attached with two more 1" nylon 4-40 screws and nylon hex nuts.

When you are done, you should have something that looks like the picture.

Step 4: Start Wiring

Put the terminal block into the right hand wall.  Put one stainless washer on each of the binding posts.  Screw one end of the pre-stripped wires into the terminal block and the other side onto the binding posts.

Step 5: Finish Wiring

The next step is to finish wiring.  The wiring diagram is shown above- as long as you follow that diagram you should be fine.  Basically, between the high voltage boost converter and the positive terminal you want to attach a switch and between the positive terminal of the LED panel and the positive terminal you want a switch as well.

To do this, you need to take the stripped ends of the wires for all the electronics and attach them to the binding posts so that they are attached to each other electrically.  This is done by wrapping the ends of the wire around the binding posts, and sandwiching them between stainless steel hardware.  Always put washers between wires, and always put washers on the end of stacks of fasteners.

For the post closest to the edge, you will want to connect the positive wire from the terminal (It should be marked with a ) to both of the switches, and the power for the voltmeter.  The exact stack from bottom to top is:

stainless washer
wire to the positive terminal of the barrel connector block
stainless nut
stainless washer
switch wire
stainless washer
stainless nut
stainless washer
switch wire
stainless washer
stainless nut
stainless washer
red wire from voltmeter
stainless washer
stainless nut

For the other binding post, you will need two separate areas of conductivity.  You will also need to be careful to hook up the right switch so that switch near the voltmeter turns on the power, not the leds.  From top to bottom, this stack is:

stainless washer
wire to negative terminal block
stainless washer
stainless nut
stainless washer
wire to -in of the boost converter (see last image)
stainless washer
stainless nut
stainless washer
black wire from LED panel
stainless washer
stainless nut
nylon nut
stainless washer
switch wire from the lower switch (not next to the voltmeter)
red wire from LED panel
stainless washer
stainless nut

Now that that is all done, you can test the led panel.  Plug in the power- the LEDs should light up when you press the button!

There are two more connections to make- the connections that conduct power to the gel tray.  These come from the out and - out of the boost converter.  These are made to the clear piece of plastic shown in picture 4.  With the notch facing away from you, the blue wire from the voltmeter should be bolted to the out wire on the right side, and the - out wire should be bolted to the left.  Look at picture 4 if you are confused- it is much easier to explain with a picture.

That's it for wiring!  Lets close it up!

Step 6: Assemble the Back

Now it is time to assemble the structure of the box.  There are only two pieces you need to find now.  One is a large rectangular clear piece with no holes in it, and the other looks just like the plate in picture 4, only it has no cutout for the terminal block in it.  combined with the backslash, which has the blue voltmeter wire bolted to it, and the wall with the terminal block in it, these four pieces make the four side walls of the electrical compartment.  The backsplash goes in the middle groove, while the back (large rectangular piece) goes in the groove closest to the power supply.  The side wall with the adapter goes close to the binding posts, and the last side wall is opposite that.  Check out picture 2 for a view of the side wall without the hole.

Once the pieces are in, fit the tops of the four pieces into the top orange plate.  The box is almost done!  Now the next step is to add the spacers and bolts.  Grab two .75" long spacers and one .125" spacer.  These support the very back of the box.  You can see this in picture four.  Both of the back boltholes use this stack of spacers.  Put them under the mounting hole and let a 2" black oxide finish 4-40 drop through them.  Then cap the screw with an acorn nut.  Make sure the nut is on the bottom of the box-it acts as a foot for the box.

The front four stacks of spacers are slightly different, because they do not have .125" spacers in them.  To install these spacers first slot in the saftey walls and place the shelf on top of them.  See pictures 2 and 3 for reference.  Then a spacer goes on the top and bottom of the shelf, and a 2" long 4-40 screw drops through the spacers.  All of these bolts screw into acorn nuts.  At the point, the box is finished!

Step 7: Tray Assembly

The tray should come pre-assembled, but if you want to make your own, you will need:
  • A tray wall
  • a tray bottom
  • 2x 7/16 pan head 18-8 stainless steel screw
  • 2x 7/16 pan head nylon screw
  • 4x nylon acorn nut
  • 10" of 316 stainless steel wire
Simply bend the wire around the steel screw and into the tray.  The wire should lay flat against the bottom of the tray.  See picture 2.

The stainless steel bolts should be on the same side of the tray.  Make sure the notch on the outside of the tray is on the left when the steel bolts are facing away from you (picture 2)

Install nylon screws on the opposite side, and put acorn nuts on all the exposed screw threads.
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    23 Discussions

    I think I really like this idea.

    We are in the middle of assembling the parts for this project. Could we ask do we need at any point to "weld" or glue the acrylic together? Or is everything accomplished by using bolts and possibly the use of silicone sealing? It doesn't look like it is necessary but we just thought we'd ask. Thanks and thanks for the Instructable!

    This is a super cool project, I just have one question. I can't seem to find a 12-30v input 60-100v output high voltage boost converter. Do you have a link to where you got yours? Or did you make it yourself? Thanks!

    2 replies

    Or perhaps jost a shopping list of where you got all of your parts?

    Is stainless steel sufficiently resistant to corrosion for this to work? The wire of choice has been platinum because other metals corrode very quickly. Platinum is very expensive, but is considered essential in spite of this. Does the steel wire need to be replaced often?
    One alternative electrode material is graphite. With some modifications, graphite that is used for drafting pencils (these are rather thick pencil 'leads' instead of the less than 1 mm ones common for writing pencils). It's durable and inexpensive when used for electrophoresis.

    3 replies

    This stainless should be tough enough to take quite a few cycles. 316 is the most corrosion resistant stainless I could find, and the process used to make it produces a very uniform surface finish, leaving less surface area for corrosion. In my testing I have never seen a failure of an electrode. Even if the electrodes are exhausted after 100 cycles, it is cheaper than platinum, and they are easy to replace and easy to buy. Platinum is about $14/inch, while stainless is $.03/inch. My decision to go with stainless instead of graphite is because graphite is soft and relatively brittle, and it is difficult to connect to things electrically (again, compared to stainless wire).

    This is part of what makes this system so good- you can buy tons and tons of the gel boxes with electrodes, and pre-pour and store them. Compared to conventional systems where the box itself costs $400 or pre-cast systems that cost $10 (about 10x the cost of an blue light fluorescent gel) per gel, this is much cheaper in the long run. You get the convenience of the pre-cast with the re-usability of the $400 box.

    what type of stainless steel do you use? There are a bunch of different ones, 316, 317L etc. Which one works the best?

    In truth, it was many years ago, and I do not remember the details. You are correct about the fragility of graphite, and if your materials work, then I cannot contradict you. You do a great service to education and research by publishing this instructable.

    I assume you mean the dimensions of the box itself- I dont have them posted yet, but the puctures should make it clear where and how things connect. I dont know if you can print one of these, but you are welcome to try.

    Nice work! Good to have an alternative to the $900 units from vwr.

    hey great idea

    Hey Tequals0!

    I've been following your wordpress for a while. Remember me? I'm the guy who gave some example PCBs for your USBTinyISP.

    I've been following your gel electrophoresis system for a while. You've come a long way.


    2 replies