Morphological and Mechanical Properties of Engineered Living Materials Reinforced by Filamentous Cyanobacteria

ABSTRACT Photosynthetic engineered living materials (PS‐ELMs) comprise an emerging field that leverages the photosynthetic metabolism of microorganisms embedded in abiotic materials to impart dynamic properties and responses. While PS‐ELMs have shown promise in several applications including bioremediation, biosynthesis, and shape‐morphing, these materials typically possess poor mechanical properties. Inspired by fiber‐reinforced, non‐living hydrogel systems, in this work we demonstrate incorporation of the filamentous cyanobacterium Nostoc commune as living fibers to reinforce PS‐ELMs. Furthermore, we investigate the relationship between filamentous bacteria and porous materials by characterizing the morphology, growth, and spatial location of Nostoc commune within alginate hydrogels. Lastly, we modulate the material system with a CaSO 4 slurry to enable direct‐ink‐writing 3D printing. These results show that filamentous cyanobacteria can act as living fibers to reinforce the PS‐ELM, in addition to providing a framework to analyze the interaction of multicellular microorganisms with materials.