Continuous efforts have been directed towards controlled calcium carbonate biomineral synthesis in recent years. Compared to their inorganic counterparts, biominerals are more tensile in industrial applications, biocompatible with scientific designs, and sustainable for the environment. Most current approaches for synthetic biomineral production rely heavily on sophisticated engineering techniques to constrain the physical property of their crystals, which limits the adaptability of these products. Here, we proposed a novel approach to synthesize calcium carbonate biominerals by reproducing skeletogenesis of the sea urchin larva in vitro using common cellular and molecular methods. Skeleton formation in Lytechinus variegatus sea urchin embryos is a highly coordinated event, where ectodermal cells in different domains express distinct patterning cues that are received by adjacent primary mesenchyme cells (PMCs), which in turn secrete the skeleton. Our group and others have identified a range of skeletal patterning cues, and based on our current understanding of the mechanism, we envisioned a synthetic ectoderm culture using defined ectodermal lineages that, when combined with PMCs, will direct the synthetic production of skeletal structures. Here we have developed a detailed protocol for establishing such as ectoderm culture and have begun initial experiments towards this goal. Future deployment of this protocol will provide invaluable insights into the mechanism of skeletal patterning in sea urchins, as well as an unprecedented system for customized synthetic calcium carbonate biomineral production. Finally, improving our mechanistic understanding of skeletal patterning in echinoderms has the potential to shed light on analogous biomineralization processes in other species as well. / 2024-10-03T00:00:00Z