Encapsulating cells—both prokaryotic and eukaryotic—allows researchers to carry out experiments in hydrated environments over prolonged periods of time. However, cell growth under these conditions can exert a lot of pressure on the encapsulating shells, resulting in cell leakage. In a new study, researchers at the University of Illinois Urbana-Champaign have developed modified alginate hydrogels that can endure the growth of bacteria, allowing them to synthesize important enzymes.