I am trying to build a small horizontal electrophoresis chamber from scratch. I want to use it for comet assay and I will be using only 1 slide, so it's going to be about 3cm wide, 10cm long and 4cm high, just enough to fit the slide and a small amount of buffer. As far as I know such thing is not commercially available, so before I make it I want to make sure that it's going to work. The main issue is the cost of the electrode (has to be platinum wire). I don't want to spent that much money just to realize that it doesn't work. My question is: is a 3cm electrode in a 60-70cm3 enough? Basically, are there any physical restrictions on the size and the position of the electrodes and the shape of the chamber? Since I am a biologist and my knowledge in physics are quite limited, I would greatly appreciate any information about this.
These instructions for building an electrophoresis chamber don't comment on the minimum length of wire, but on the other hand they suggest using something called Monel Seizing Wire (Ni/Cu alloy - £8.95 for 10 m in the UK) or 20-gauge copper wire, so if you follow their advice you probably don't need to worry about cost.
I imagine that alloy electrodes won't last as long, but they would be cheap to replace - in fact you would be looking for opportunities to use up all of your excess wire!