Biological networks are complex, and effective therapies may require combinations of drugs to overcome redundancies, feedback mechanisms, or drug resistance. Such screening is challenging because of the multiplicity of combinations to test. Kulesa et al. describe a miniaturized process that automatically creates drug combinations from nanoliter-scale droplets. Emulsions were made of a chemical compound, cell culture, and a fluorescent barcode. Pairs of droplets were loaded into wells of a microarray plate and mixed, and cell growth was monitored. This platform was successfully used to identify previously unsuspected drugs that synergize with antibiotics to kill Escherichia coli.
