At the heart of our platforms are picodroplets. These are tiny droplets of aqueous fluid in an oil carrier fluid (a ‘single emulsion’) or an aqueous core surrounded by an oil shell in an aqueous carrier fluid (a ‘double emulsion’). Each picodroplet is used to encapsulate a cell. The chemistry of the emulsions is carefully designed to give long-term stable, biocompatible droplets with minimal leakage of molecules from the droplet, right down to small molecules such as metabolites. This provides an ultra-miniaturized test tube, containing media, reagents, and cells, that allows large-scale experiments at the single cell level.