forensic science:building your own tool for identifying DNA

[deleted-94592]

I have made the agarose gel mixture but it is not setting..I used all the materials..it has been 3 days and this gel is not solidifying ..PLEASE HELP!my project is due next week please help me!!!!

[deleted-93346]

Sorry you are having difficulties. This is one of our most challenging projects, but it is doable and you will gain in proportion to the effort it takes.

I am not an expert on the preparation of the gels. I have put out a request for one of our experts who is familiar to help you, so watch for his or her reply.

Meanwhile, looking over the procedure write up I spotted two places where it would be easy to make a mistake. First, the bottled water you use is NOT something like Evian, meant for drinking. It is de-ionized or distilled water meant for use in steam irons or humidifiers -- so check the label on your bottled water. Second, use baking soda (sodium bicarbonate) NOT baking powder, which is entirely different.

Finally, here is a link to an older thread that may be relevant:

https://www.sciencebuddies.org/science- ... gel#p33409

Good luck, and say tuned!

[sunmoonstars]

Hi,

John did give you some great advice to start. I wonder if you bought the supplies separately or if you purchsed a Science Buddies kit from this list? https://www.sciencebuddies.org/science- ... ?From=AAE

Some important things to point out - he did mention that the water used is important, you want the distilled, deionized water, not just bottled water. At my grocery store you can get a gallon jug of distilled water for about a dollar. It should say distilled water on it - this is the right one. Other waters have minerals and such in them that can inhibit the gelling.

Also, make sure the baking soda was used (sodium bicarbonate) and that it is pretty fresh, so it is still active and will give the right pH in your buffer solution.

Another thing to consider is if the correct amount of baking soda and agarose are used: if you cannot weigh out the amounts, guidelines for volume measurements were given (1/2 tsp baking soda and 1/4 tsp agarose) - but don't use ordinary kitchen utensils as these are not accurate. You need measuring spoons (like these http://www.bedbathandbeyond.com/product ... U=11508030) for accurate measuring... and the powder should be leveled off at the top, not heaping over.

Now, even if the meausr is off a little bit (not alot), the gel should still be able to set, but it would be of different agarose concentration than you would expect, so...

Make sure the agarose came to a boil before you stop microwaving it. This is very important, because the agarose has to be boiled and completely in solution before it will be able to solidify as a gel when it is cooling.

I am sure if you check each of these things, you can try again and get this experiment to work. It IS one of the more challenging projects, but really exciting once you get it going

Please let me know if you need more help with this!

Tonya

[SarahJoy]

My food colors didnt travel through the gel. i didnt do anything wrong!

[sunmoonstars]

My food colors didnt travel through the gel. i didnt do anything wrong!

Hi SarahJoy,

If the colors did not migrate through the gel, something didn't go as expected. It seems like you mention you had trouble grinding the flower petals up into a liquid before loading in the chamber. This is a very important step - not only does the sample you load have to be a liquid, but it has to be broken down in the liquid very fine so it can move through the tiny pores in the gel after it solidified.

If you are using this Project Guide:https://www.sciencebuddies.org/science- ... p028.shtml , you could try using the food coloring liquid they mention first to see if everything else is okay with your setup. Then if that works, you could focus on getting those petals ground up very nicely and into a solution for loading in the chambed.

Please let me know if you need further help on this, and when you try again, how it worked for you.

Good Luck!

Tonya