National Research Center for Geoanalysis, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Dajie, 100037 Beijing, China.
Evid Based Complement Alternat Med. 2011;2011:540987. doi: 10.1155/2011/540987. Epub 2011 Sep 4.
The depth of the ocean is plentifully populated with a highly diverse fauna and flora, from where the Challenger expedition (1873-1876) treasured up a rich collection of vitreous sponges [Hexactinellida]. They have been described by Schulze and represent the phylogenetically oldest class of siliceous sponges [phylum Porifera]; they are eye-catching because of their distinct body plan, which relies on a filigree skeleton. It is constructed by an array of morphologically determined elements, the spicules. Later, during the German Deep Sea Expedition "Valdivia" (1898-1899), Schulze could describe the largest siliceous hexactinellid sponge on Earth, the up to 3 m high Monorhaphis chuni, which develops the equally largest bio-silica structures, the giant basal spicules (3 m × 10 mm). With such spicules as a model, basic knowledge on the morphology, formation, and development of the skeletal elements could be elaborated. Spicules are formed by a proteinaceous scaffold which mediates the formation of siliceous lamellae in which the proteins are encased. Up to eight hundred 5 to 10 μm thick lamellae can be concentrically arranged around an axial canal. The silica matrix is composed of almost pure silicon and oxygen, providing it with unusual optophysical properties that are superior to those of man-made waveguides. Experiments indicated that the spicules function in vivo as a nonocular photoreception system. In addition, the spicules have exceptional mechanical properties, combining mechanical stability with strength and stiffness. Like demosponges the hexactinellids synthesize their silica enzymatically, via the enzyme silicatein. All these basic insights will surely contribute also to a further applied utilization and exploration of bio-silica in material/medical science.
海洋深处栖息着丰富多样的动植物群，其中包括来自“挑战者号”探险队（1873-1876 年）采集的丰富的玻璃质海绵[六放海绵纲]。这些海绵由舒尔茨描述，代表了最古老的硅质海绵[多孔动物门]类群；它们引人注目，是因为它们独特的身体结构，依赖于精细的骨架。这个骨架由一系列形态确定的元素，即骨针，构建而成。后来，在德国深海探险“瓦尔迪维亚号”（1898-1899 年）期间，舒尔茨能够描述地球上最大的硅质六放海绵，高达 3 米高的 Monorhaphis chuni，它形成了同样最大的生物硅结构，巨大的基骨针（3 米×10 毫米）。以这些骨针为模型，可以详细阐述骨骼元素的形态、形成和发育的基础知识。骨针是由一种蛋白质支架形成的，这种支架介导了硅质薄片的形成，蛋白质被包裹在其中。多达 800 个 5 到 10 微米厚的薄片可以围绕一个轴向通道同心排列。硅质基质由几乎纯的硅和氧组成，赋予它独特的光物理特性，优于人造波导。实验表明，骨针在体内作为非眼光感受器系统发挥作用。此外，骨针具有特殊的机械性能，将机械稳定性与强度和刚度结合在一起。与寻常海绵一样，六放海绵通过酶硅酸盐合成其硅质，这种酶叫做硅质体。所有这些基本的见解肯定也将有助于进一步应用和探索生物硅在材料/医学科学中的应用。
