Question: "It’s made of Aluminium because it needs to conduct heat." you said that, but why does it need to conduct heat?

Amelia Markey answered on 16 Jun 2011:

Good question!

So the way I copy DNA is by a technique called Whole Genome Amplification or WGA for short. This works in a similar way to the way DNA is copied in your body but the reaction has 3 stages. First I need to denature the DNA. DNA is made of two strands and when you denature it you break these strands apart so each one can be copied. It’s a bit like taking the staple out of a wad of paper so you can photocopy each individual page. This step takes place at 95 degrees C. The next step is to copy the DNA. The enzyme (or protein catalyst) that does this needs a temperature of 30 degrees C. The last step is to inactivate this enzyme because if you leave it active it will start chopping up the DNA it’s already made (bit silly really), to do this you need to heat the enzyme to 65 degrees C.

Now you may have noticed that my device only has 2 regions! This is because I have shown the DNA can still be copied even if you don’t break the strands apart. So you can miss out this first step and it means my device can be less complicated. The bit around the outside of my device is heated to 30 degrees C and the copying stage takes 4 hours. Then the middle bit is set to 65 degrees C and this will inactivate the enzyme in 10 minutes.

So because I have all these temperatures I have heat mats under the aluminium block that are set to these different temperatures. I need a really nice conductive material like Aluminium so that the heat generated by these mats is spread evenly over the whole of the block and I don’t have any hot or cold spots where the reaction wouldn’t work as well.

Hope that answers your question!