Biomineralization of coral fragments: influence of local chemical composition on self-attachment, morphology, growth and microstructure

About This Grant

Non-Technical description Engineering living materials is a promising strategy to develop smart, resilient materials that can grow, adapt, and repair themselves, expanding possibilities in next-generation materials science and engineer-ing. A striking example of nature’s ingenuity in creating living materials is the way it regulates bio-mineralization in coral reefs. These dynamic structures not only provide crucial support for marine life, coastal protection, and local economies, but also serve as a source of bioactive compounds with poten-tial as drugs for treating cardiovascular diseases and cancer. If a coral fragment is detached from the main colony and attached to a substrate, the wound heals, allowing the fragment to grow into a new cor-al. While this process, known as coral fragmentation (or fragging), presents a promising strategy for cor-al conservation and restoration, fragging also offers a pathway for developing coral-inspired living mate-rials. However, the fundamental understanding of the processes involved remains quite limited from a materials science perspective. The goal of this project is thus to advance from infancy to maturity the understanding and control of coral fragment biomineralization. The project outcomes advance the sci-ence of biomineralization and how it can be used to design materials that live, grow, and heal— inspired by corals. Broader impacts of this project include training two graduate students at the intersection of materials science and biomineralization and hosting undergraduate students in the principal investiga-tors´ lab to further develop their interests in materials science, thereby enhancing the STEM pipeline. Discoveries in coral-inspired living materials have the potential to drive economic prosperity through product innovation and new markets, while simultaneously improving societal welfare by enhancing health and safety. Technical description The goal of this NSF project is thus to advance the knowledge of the biomineralization processes in cor-al fragment healing and growth and how these processes relate to the resulting material properties. Moreover, the project provides insights into how to influence early-stage coral biomineralization and material properties by tuning the substrate composition and/or water chemistry, i.e., the local chemical environment around the fragment. To achieve this goal, the project tasks are to (i) study the self-attachment of (micro)fragments and the mineralization at the body basal wall, (ii) characterize fragment growth and the evolution of skeletal morphology, (iii) elucidate the evolution of fragment microstructure during early growth (2–3 years) after attachment and the biomineralization pathway, and (iv) understand the effects of extrinsic parameters (substrate composition, water chemistry) and fragment size on growth, properties of (micro)fragments, and the biomineralization pathway. Focusing on fragments of two spe-cies of reef-building scleractinian corals (Echinopora lamellosa and Favia fragum), the experimental plan includes an in-depth study of early-stage calcification during self-attachment using advanced liquid-cell transmission electron microscopy. Additional knowledge is obtained from a comprehensive dataset encompassing coral morphology, growth rates, and skeletal microstructure and composition using in-house techniques such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, and nano-computed tomography with submicron resolution. These studies are complemented by experiments with collaborators at Argonne National Laboratory to determine the skeleton composition. Overall, the insights gained from this research contribute to establishing design principles for coral-inspired living materials and advance the knowledge about biomineralization processes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.