Structural biomaterials are hierarchically organized and biofabricated. Although the structural complexity of most bioskeletons can be traced back from the millimeter-scale to the micrometer-or submicrometer-scale, the biological and/or genetic basis controlling the synthesis of these skeletons and their building blocks remained unknown. There is one distinguished example, the spicules of the siliceous sponges, for which the principle molecules and molecular-biological processes involved in their formation have been elucidated in the last few years. In this review, recent data on the different levels of molecular, biological and structural hierarchies controlling the synthesis of the picturesquely and intricately architectured spicules are summarized. The silicateins and their interacting/maturated proteins comprise the basic enzymatic/proteinous machinery that facilitates the polycondensation of silicate to biosilica. Two isoforms of silicatein, silicatein-a and silicatein-b, the enzyme that catalyzes Xiaohong Wang Xiaohong Wang became a Full-Professor at the National Research Center for Geoanalysis (Chinese Academy of Geological Sciences) in 2005. She received the award of Excellent Young Scientist at the Ministry of Land and Resources, China in 2003. At present, she is working at the University Medical Center of the Johannes Gutenberg University of Mainz (Germany), where, together with Prof. Dr W. E. G. M€ uller, she is coordinating the Joint German-Chinese Laboratory on 'Nano-Bio-Composites'. Her major interests are processes of biomineralization of siliceous sponge spicules and their bionic applications, with the aim to develop biologically inspired medical materials.