Jochen Zimmer explores how cells build extracellular skeletons, protective barriers, and intercellular connectors. Zimmer and his team examine in molecular and mechanistic detail extracellular carbohydrate-based materials such as microbial biofilms and capsules, plant cell walls, insect exoskeletons, and the vertebrate glycocalyx. The materials comprise extracellular polysaccharides (EPS) such as cellulose and chitin and are key to cell viability, as well as many biomedical and industrial applications. Zimmer and his team want to know how EPS are synthesized and integrated into a 3D extracellular matrix. Working in model organisms, they combine molecular, membrane, and structural biology with glycobiology and biophysics. This work has potential implications for the development of novel biomaterials.