The present invention provides novel microfluidic devices and methods that are useful for performing high-
throughput screening assays and
combinatorial chemistry. Such methods can include labeling a
library of compounds by emulsifying aqueous solutions of the compounds and aqueous solutions of unique liquid labels on a microfluidic device, which includes a plurality of electrically addressable, channel bearing fluidic modules integrally arranged on a microfabricated substrate such that a continuous channel is provided for flow of immiscible fluids, whereby each compound is labeled with a unique liquid
label,
pooling the labeled emulsions, coalescing the labeled emulsions with emulsions containing a specific
cell or
enzyme, thereby forming a
nanoreactor, screening the nanoreactors for a desirable reaction between the contents of the
nanoreactor, and decoding the liquid
label, thereby identifying a single compound from a
library of compounds.