Understanding biocrystallization in dinoflagellates: From biological fundamentals to functional hybrid materials

The research group focusses on biocrystallization processes in dinoflagellates, including calcium carbonate, anhydrous guanine and cellulose and their materials aplication.

For 500 million years algae have shaped our environment by fixing CO2 through the precipitation of minerals. This biomineralization gives rise to a variety of complex architectures with spectacular morphologies. A paradigm example of regularity in biological systems are the highly ordered, porous shells of unicellular dinoflagellates made of calcium carbonate. Their long-range morphological regularity is beyond the reach of current technology.

During the last decades, significant progress has been made in understanding the key biochemical mechanisms responsible for biomineral formation in model organisms like diatoms or coccolithophores. In contrast, the mechanisms that control the intricate mineral construction in dinoflagellates are practically unknown. This is very surprising, because structure formation does not take place in an intracellular, deposition vesicle, but instead in a less controlled, extracellular space, the so-called outer matrix. This makes dinoflagellates a well-suited model system especially in view of biomimetic materials synthesis. Together with the group Lia Addadi and Steve Weiner (Weizmann-Institute of Science) we developed a new dinoflagellate biomineralization model. However, many details of structure morphogenesis are still not understood.

To study calcium carbonate biomineralization in dinoflagellates we combine spectroscopic techniques (ICP-OES, vibrational spectroscopy, NMR, mass spectrometry incl. nano-SIMS) with advanced bioimaging (in vivo-fluorescence, cryo electron microscopy, FIB-SEM-EBSD) as a most promising approach.

In addition, we aim to generate dinoflagellate-based biomaterials. Mesoporous structures are an increasingly important class of materials with high significance in many technological domains. Bio-derived mesoporous systems are even more compelling because of their biocompatibility. For this reason, we aim to combine the biological fundamentals of structure formation with materials applications, especially in catalysis, optics and as functional microcapsules.

Another focus of our work is the function of anhydrous guanine crystals in dinoflagellates. Guanine crystals are used by certain animals, including vertebrates, to produce structural colors or to enhance vision, because of their distinctive reflective properties. Today, about half of the global production of oxygen is carried out by algal photosynthesis in the oceans. In C.operosum aff. the deposits of anhydrous guanine crystals are closely associated with the chloroplast network. We investigate whether the guanine crystals influence the cell’s photosynthetic performance.