In vitro evolution in microfluidic systems

A method for conducting an enzymatic reaction, comprising the steps of:

• providing a droplet generator to produce, under microfluidic control, a plurality of aqueous microcapsules surrounded by an immiscible continuous phase that comprises a fluorinated oil that comprises a fluorinated polymer surfactant, each of the plurality of microcapsules comprising an enzyme, a genetic element linked covalently or non-covalently to a bead, and reagents for the enzymatic reaction;
• pooling the microcapsules into one or more common compartments such that a portion of the plurality of microcapsules contact each other but do not fuse with each other due to the presence of the surfactant;
• and
• conducting the enzymatic reaction on the genetic element of at least one of the plurality of microcapsules within the one or more common compartments.