I’ve been approached by my squid scientist friend, Heather, to make a custom tray and combs for casting agarose electrophoresis gels so that she can run 96 PCR products at a time. Gel combs are pieces of plastic which are plunged into the liquid agarose before it sets to form wells in the solid slab that you can load with the product of your PCR run.

This is the kind of lab gear which costs fantastic sums to purchase from vendors, particularly with any sort of bespoke customisation. Have a look at Thermo Scientific or Sigma Aldrich’s web site, where you will find these little pieces of plastic on sale for around NZ$100 each.

This type of thing is a very straightforward object to design and make for anyone with a few CAD skills and access to a lasercutter. I knocked up a design in about 5 minutes to demonstrate this to Heather and she got very excited and set off to measure up exactly what she wanted.

Here’s the OpenSCAD code for this object:

translate([0, 0, 13 /2])
cube([133, 1.5, 13], center=true);

translate([0, 0, -3 /2])
cube([122, 1.5, 3], center=true);

for(x = [-6:1:6]) {
translate([x *9, 0, -6.5])
cube([4.5, 1.5, 10], center=true);
}

Pretty simple, huh?

I have some clear 6mm thick acrylic sheet which I can use for the gel-casting tray and I’m going to order some 1.5mm acrylic sheet from RS to cut the combs from. In exchange for my help I get to post the design here on my blog so win-win!

Update

I’ve sketched out the design and its looking great. I’m going to do a test cut in MDF first to see how it fits together.