Upgrading old Caralina Electrophoresus for Dye

[bigmack]

We have had an older DNA electrophoresis kit .It originally cost around $500 . Then we bought a replacement kit at just under $200 .( this contains Another lot of Cut DNA samples , Carbon fibre electrodes , TBA buffer sol"n , stain and the ridiculously expensive Agarose powder .
Twice in the last two years it's been dragged out and teacher ended up with poor or no results .
I had the job of retesting it all and we concluded that the DNA samples must be completely useless due to their age .

Carolina Electrophoresus kit.jpg

The Head teacher said "no way can we spend $200 for a fresh lot of samples and expendables every time a teacher wants to do this Prac".
So We decided to get the Dyes from Southern Biological and give that a go as it only requires an electrolyte of Sodium Bicarbonate instead of the TBA buffer Solution . Also standard agar powder can be used instead of the Agarose .

Dye Electrophoresis is slightly different to DNA Electrophoresis in that the Dyes can have either a positive or negative charge so needs to be positioned in the middle of the Gel unlike DNA which is started at one end .
Alas out trays only had slots at the end to fit the well combs so I had to carefully make slots in the middle to suit the new comb position .This involved cutting a slot with a jeweler's saw to equal length as the original so that the combs set into the Gel the same depth

Setting agar.jpg

Another issue with our old trays is that they require a carbon fibre electrode which has to be cut to fit each use and then thrown away.
(Now all these problems could have been avoided if we just shelled out $185 each for new trays with Platinum electrodes built in . )...but that wasn't going to happen .

[bigmack]

original carbon fibre electrodes.jpg

Anyways, I made up some electrodes out of carbon electrodes we had here and secured them in place with a copper clip which the alligator leads clip to .

carbon electrodes.jpg

Testing carbon electrodes.jpg

This means we no longer need to buy the replacement kits @ $200 to run this prac and can now do it with a $27 set of Dyes that will give us around 45 tests per dye sample....with 5 Gel trays , that's about 9 pracs

The only other thing I'm looking at is making a voltage multiplier circuit to fit to our Power supplies so we can get the required 40 odd volts to run this . In previous years we had multiple 9 volt batteries in series ....another huge cost ..

Or we could just buy the correct power supply , its only around $400

[Merilyn1]

Wow, well done! You can hang out in my prep room any time you like - I'll give you all my "problem" bits of equipment to sort out.

[bigmack]

Thanks for the offer Merilyn
LOL , but seriously it was Athletics Carnival yesterday and there is only sooo much Labeling you can do

I hate seeing expensive gear sitting around either because its not working or it's too expensive to run. The Dept had already thrown a good $750-$800 at this kit for effectively two successful Pracs .
If I had not done what I did it would need another $200 every time someone wanted to use it . This way it will be accessible to more classes .
The cost to run it is a $ 27 Dye kit which lasts about 9 Pracs .

I made up some practice Dyes out of Bromothymol Blue powder and Methyl orange powder in a 20/80 glycerol /water mix . The kids can practice away with their 10uL micropipettes , befor we let them loose on the expensive Dyes

[RosalieL]

bigmack - I'm curious! I've just bought the BandIT from southern bio that uses these dyes. Do they work just as well in normal agar instead of agarose? And the buffer of bi carb soda - what concentration do you use?

I bought some practice wells with it so my plan was to use food colouring in glycerine for the loading practice. Is there a reason you chose those specific dyes? or is it just what you had on hand? I haven't tried it yet so I don't know if the food colour will come out of the glycerine into the water while they're loading the wells.

[bigmack]

Hi Rosalie

Yes you can just use plain Agar .It’s one of the beauties of the dye .No more expensive Agarose powder .
Also yes I used Bicarb soda as the electrolyte but I can’t remember the concentration . I could find out for you though .

As for the dyes , the set I got had a little sticker on them saying what they were and the concentration . I only had Bromothymol blue and Methyl orange on hand , so thats what I used . Maybe food dyes will work too . Never tried them though :

EDIT : The electrolyte solution is also used to make the agar instead of using water .