Losic Dusan, Rosengarten Gary, Mitchell James G, Voelcker Nicolas H
School of Chemistry, Physics and Earth Sciences, Flinders University, Bedford Park, Adelaide, Australia.
J Nanosci Nanotechnol. 2006 Apr;6(4):982-9. doi: 10.1166/jnn.2006.174.
Diatoms produce diverse three-dimensional regular silica structures with nanometer to micrometer dimensions and hold considerable promise for biological and biomimetic fabrication of nanostructured materials and devices. In the present work, we describe the ultrastructural characterization of porous structures in diatom biosilica and discuss their potential as membrane filters for diffusion based separations. The frustules of two centric diatom species, Coscinodiscus sp. and Thalassiosira eccentrica, were investigated using scanning electron microscopy and atomic force microscopy. Their morphological features, including pore size, shape, porosity, and pore organization, are described. We observed that although pore organization in frustules of Thalassiosira eccentrica and Coscinodiscus sp. is in reverse order, a striking commonality is the size range of the smallest pores in both species (around 40 nm). The consensus lower pore size suggests that frustule valves have a common function at this size of excluding viruses or other deleterious particles, and the pore size and organization is optimized for this purpose. We suggest and implement an experimental approach to study the potential of diatom frustules for diffusive separation of molecular or nanoparticular components in microfluidic or lab-on-a-chip environments.
硅藻能产生具有纳米到微米尺寸的各种三维规则二氧化硅结构，在纳米结构材料和器件的生物及仿生制造方面极具潜力。在本研究中，我们描述了硅藻生物二氧化硅中多孔结构的超微结构特征，并讨论了其作为基于扩散分离的膜过滤器的潜力。使用扫描电子显微镜和原子力显微镜研究了两种中心硅藻物种——圆筛藻属（Coscinodiscus sp.）和偏心海链藻（Thalassiosira eccentrica）的壳套。描述了它们的形态特征，包括孔径、形状、孔隙率和孔结构。我们观察到，尽管偏心海链藻和圆筛藻属壳套中的孔结构顺序相反，但一个显著的共同点是两种物种中最小孔的尺寸范围（约40纳米）。一致的较小孔径表明，壳套瓣膜在这个尺寸下具有排除病毒或其他有害颗粒的共同功能，并且孔径和结构为此目的进行了优化。我们提出并实施了一种实验方法，以研究硅藻壳套在微流体或芯片实验室环境中对分子或纳米颗粒成分进行扩散分离的潜力。
