Abstract
Once the DNA amplification is done we need to generate a signal. To do so, we decided to regulate the expression of a protein that will create a color change by using a toehold switch. First we designed three toeholds, one for both diseases and the control. Then we had to bind the toeholds with a protein. We chose sfGFP to make our measurements as we knew it can be expressed in OnePot PURE and easily measured on the plate reader. However, since we want our test to be field-deployable, a colorimetric signal is better than a fluorescent one. To solve this problem we used an enzyme called CDO (catechol 2,3-dioxygenase). This enzyme cleaves the substrate catechol and creates a change of color from transparent to yellow.