Abstract
The idea of compartmentalization of genotype and phenotype in cells is key for enabling Darwinian evolution. This contribution describes bioinspired systems that use in vitro compartments-water-in-oil droplets and gel-shell beads-for the directed evolution of functional proteins. Technologies based on these principles promise to provide easier access to protein-based therapeutics, reagents for processes involving enzyme catalysis, parts for synthetic biology and materials with biological components.