Figure 4.

The automated workflow programmed to run kinetic assays. Schematic diagram of the four steps that provide a full set of Michaelis–Menten data: (1) loading of the droplet pairs corresponding to different points of the Michaelis–Menten plot; (2) confirming and sizing of the droplet pairs prior to fusion; (3) droplet merging in tubing initiates the reaction; and (4) droplets are moved back and forth for reading of the reaction progress by absorbance. Such readings can be repeated many times until the reaction has advanced sufficiently to describe a full time-course. The ability to carry out as many measurements as necessary makes this system amenable to most reactions (with time scales from a minute to several hours or more). The sizing data (step 2) and the data for the time-courses (step 4) were stored in individual files. This process can be repeated for multiple samples that are sequentially supplied from the carousel of the robotic sampler (Figure 1A).