Gel electrophoresis system (mini)

Instructables tutorial for making a mini-gel electrophoresis system for DNA analysis. Gel electrophoresis systems are essential tools for any molecular biology research, but are often expensive to buy. The total cost of making this DIY system is around $50-$80, depending on where you source the laser cut acrylic parts.

Almost all of the assembly steps described in this tutorial require solvent welding the custom laser cut acrylic parts together using Weld-On #4, a fast-setting, clear, thin liquid cement. Weld-on is applied to the edge with a syringe applicator and drawn into the contact surfaces by capillary action. It is actually an easy and quick procedure, however, be sure to practice welding two scrap pieces of acrylic together if this a new technique to you.

The total length of time to complete assembly is 2-3 hours. Once complete, you will have the following parts:

- A UV-transmissive gel tray for casting a 7 x 7 cm mini-gel and comb;
- An electrophoresis chamber with lid.

Step 1 Parts and tools

Acrylic materials and design files

From any supplier of acrylic materials (McMaster-Carr, US Plastics etc):

12” x 12” x 1/4" clear acrylic
12" x 12" x 1/4" blue acrylic (or preferred color)
5" x 5" x 1/8" clear acrylic

From McMaster-Carr:

6" x 6" x 1/16" teflon sheet , Cat # 8545K13

From Loop Acrylics:

1/8" solacryl (UV transmissive) - Optional : If you do not need a UV-transmissive gel tray then simply make these parts from regular clear acrylic.

Using the design files attached below, cut the parts from your material - the type of material to use is given in the title of the file. If you do not have access to a laser cutter, you can send the files to any laser cutting service (we use Pololu). These services will also carry most of the material you need with the exception of solacryl.You can also purchase a kit from our online store (IO Rodeo , Cat #IMG-01) for $93. The kit contains all of the laser cut parts and hardware, platinum wire (instead of stainless steel wire) and pre-assembled combs. You will still need to buy the Weld-On and applicator.

Hardware and tools

From McMaster-Carr:

2-56 Hand Tap Taper, Cat # 2522A663
Tap Wrench Sliding T-Handle, 0-1/4" (1.6-6.3mm) Tap Size, Cat # 2546A22
2x 2-56 Nylon Pan Head Slotted Machine Screw, 3/16" Length, Cat # 93135A076
4x 2-56 Nylon Pan Head Slotted Machine Screw, 1/8" Length, Cat # 93135A074
Stainless steel wire, 0.01" diam. Cat # 9882K31
2x 6/32 Hex machine nuts Cat # 91841A007
2x Flat Washer, No. 6 Screw Size, 5/16"Cat #  92141A008

From TAP Plastics:

IPS weld-on cement #3 or 4, Cat # 10792
Hypo-type solvent cement applicator, Cat # 25658

From Digi-Key:

2x Banana plug, Cat #655K-ND
Black banana plug cable, 36", Cat # 4771-36-0-ND
Red banana plug cable, 36", Cat # 4771-36-2-ND
4x Rubber feet , Cat # SJ5012-0-ND

Comments

[dorkusmonkey]

Can you speak a bit more about the electrodes you use (what are they made of, where you got them, what kind of cost, how long they last, etc.)?

Looking around, platinum seems exorbitantly expensive for even a 2" length. I've successfully used carbon rods (i.e. artist graphite sticks) for (an admittedly ghetto) electrophoresis experiment, but these are only good for one to two uses before they break apart, often polluting the water when they do.

You chamber looks absolutely fantastic! I hope one day I'll be able to make something as professional looking!

[jorodeo]

The electrodes in the instructable above are stainless steel, which is a cheaper alternative and works well. The wire is listed in the materials above from McMaster-Carr (Stainless steel wire, 0.01" diam. Cat # 9882K31). It works really well DIY kind of projects. Eventually you will have to replace it, although I haven't had to yet and I've used it maybe 10 times I think ? I made the electroced easy to replace by using screws which fasten the wire in place. All you need is a screwdriver to replace the wire. It is admittedly abit fiddly though.

For more regular use, such as in a lab, you should use platinum wire. Yes it is pricey. I get mine from a jewelry store in New York and include platinum wire electrodes in the electrophoresis kit we sell online (www.iorodeo.com - shameless plug !). Per electrophoresis kit you need 1 ft of platinum wire. The last time I bought the wire it cost $30.69 per ft, which is the cheapest I've found so far.

[macowell]

Could you tell us more about your power supply?

[jorodeo]

The power supply I use, and shown pictured, is a Whatman Biometra Model 125 low voltage power supply that I bought last year from Labrepco for $50. The last time I looked on their website though they were not selling it anymore. I am hoping someone will come up with a cheap and open source low voltage power supply design soon.

[DIY-Guy]

Beautiful use of brainpower JoRodeo, well done!
Please, will someone post an instructable (or links) on using this? Experiments written for grade school, High School, or College level, but clearly explained in any case.

Thanks Instructables Community!

[isacco]

Congratulations for this instructable! The project is well illustrated and explained and the final object looks really professional.
I have crafted some electrophoresis chambers. However, without laser cutting, they looked "home-made". Indeed, they worked very well. The only thing I bought from laboratory suppliers is the comb.

Based on my experience, platinum is a must for the electrode wire. Stainless steel works well at first but, over time, it can release electrolytic products that contaminate the electrophoresis buffer solution.