"During the last decade, the principles of biomineralization have increasingly attracted multidisciplinary scientific attention, not only because they touch the interface between the organic/inorganic world but also because they offer fascinating bioinspired solutions to notorious problems in the fields of biotechnology and medicine. However, only one group of animals has the necessary genetic/enzymatic toolkit to control biomineralization: siliceous sponges (Porifera). Based on his pioneering discoveries in poriferan molecular biology and physiological chemistry, the PI has brought biosilicification into the focus of basic and applied research. Through multiple trendsetting approaches the molecular key components for the enzymatic synthesis of polymorphic siliceous skeletal elements in sponges have been elucidated and characterized. Subsequently, they have been employed to synthesize innovative composite materials in vitro. Nonetheless, knowledge of the functional mechanisms involved remains sketchy and harnessing biosilicification, beyond the in vitro synthesis of amorphous nanocomposites, is still impossible. Using a unique blend of cutting-edge techniques in molecular/structural biology, biochemistry, bioengineering, and material sciences, the PI approaches for the first time a comprehensive analysis of natural biomineralization, from gene to biomineral to hierarchically ordered structures of increasing complexity. The groundbreaking discoveries expected will be of extreme importance for understanding poriferan biosilicification. Concurrently, they will contribute to the development of innovative nano-biotechnological and -medical approaches that aim to elicit novel (biogenous) optical waveguide fibers and self-repairing inorganic-organic bone substitution materials."