Think back to the first time you learnt a new scientific technique. The very first time you entered the lab to put the theory into practice, you probably didn’t start with the most difficult or challenging example.
For example, at some point in your career you will probably have run a PCR to either amplify a piece of DNA you needed to use in a downstream application, or to check that a specific genetic feature is carried by the organism you were studying. You likely didn’t start by running multiple concentrations of template DNA, different dNTP or primer concentrations at different annealing and extension temperatures. You likely picked a single setting for the above variables so you could get used to the process of setting up the reaction.
In the same vein, when thinking how to start your DOE journey, pick a system that you are familiar with, rather than trying to apply a new methodology to a system that you have little to no knowledge about.
A few things you might consider:
Pick a system that you have knowledge about, and pick properties to vary that you know will impact that system.
Pick a system that you know is easy to assay. For your first time, it would be best not to pick a system that you know will be difficult to assay, or one that you need to develop an assay for (this is something that in the future you might apply DOE to in its own right!).
Pick a simple system that requires minimal experimental effort and can be cheap for you to run relatively quickly. You may have a lot of knowledge about your cell-based assay, but if it is a multi stage experimental set up that spans several days, then it will take longer and be more expensive for you to run your first DOE.
One of the aims here should be to get stuck in quickly with something that is easy.
Some ideas and suggestions might be:
A buffer optimisation for a biochemical assay
A media optimisation for a microbial culture
A formulation optimisation
To learn more about starting with a simple use case, click here.