Spatially Organized Photosynthetic Living Materials

Engineered living materials (ELMs) are emerging class of functional materials, often fabricated by incorporating living cells within an inert polymer matrix to form desired functions. Unraveling the formation, spatial localization, and behavior of cellular populations within an artificial niche is a prerequisite for predicting and intensifying the functions of living materials. This study focuses on the growth and spatial distribution of eukaryotic microalgae <i>Chlamydomonas reinhardtii</i> within hydrogel networks for the strategic fabrication of living materials with intensified CO₂ capture. Existing unicellular microalgae within scaffolds form multicellular algal aggregates, called palmelloid, around the surface of bioprints, which play a crucial role in forming the functional surfaces of materials. With increasing depth of the matrix, the number and volume of cellular clusters decrease due to photon attenuation and limited air transfer. By tailoring material thickness and increasing the exposure of palmelloid to its circumjacent environments, the CO₂ capturing performance of bioprints can be enhanced. Interestingly, material designs to regulate photosynthetic activity show similarities to the strategies for intensifying photosynthetic activity inspired by plant leaves. Our results imply that the spatial control of cell population can control the function of ELMs and can be exploited for biomimetic structural research for leaf mimicry.