OK, here’s a little taste of what I usually do, rather than some random ramblings… I have a PhD student who is running enzyme-linked immunosorbent assays, or “ELISAs” to the initiated. This is a standard technique for measuring (in a semi-quantitative way) the amount of a given substance in a sample. Basically (and this is a pretty basic description), you stick an antigen to a surface (like the bottom of a plastic tray) and then add an antibody that sticks to the antigen. The antibody has an enzyme stuck to it and when you add the substance of interest the enzyme catalyses a reaction that causes a change in the intensity of a colour. You can shine a light through the sample to see how much the colour has changed and that gives you an idea about the concentration of your sample.Read More »