School of Chemistry & Chemical Engineering, Queen's University, Belfast, UK.
J Mater Chem B. 2021 Sep 14;9(34):6728-6737. doi: 10.1039/d1tb00322d. Epub 2021 Aug 3.
Diatoms are unicellular eukaryotic algae that have a distinctive siliceous cell wall (frustule) with unique architectures. The nanotopography of the frustule is perfectly replicated between generations, offering a source of highly intricate and identical silica microparticles. In recent years, the ability to alter their cell wall chemistry both in terms of functionalisation with organic moieties or by incorporation of the metal ions in their frustules has increased interest in their utility for catalysis technologies, and semiconductor and biomedical applications. Herein we review the fundamental biological mechanisms in which diatoms produce their frustule and their ability to substitute different metal ions in their frustule fabrication process. The review focuses on the potential of diatom frustules as a naturally derived biomaterial in bone tissue engineering applications and how their cell walls, comprising biogenic silica, could either partially or fully incorporate other bone therapeutic metal ions, e.g., titanium or calcium, into their frustule. The use of diatom frustules in bone repair also potentially offers a 'greener', more environmentally friendly, biomaterial as they can naturally synthesise oxides of silicon and other metals into their frustules under ambient conditions at a relatively neutral pH. This process would negate the use of harsh organic chemicals and high-temperature processing conditions, often used in the fabrication of silica based biomaterials, e.g., bioactive glass.
硅藻是具有独特硅质细胞壁（壳）的单细胞真核藻类，其结构独特。壳的纳米形貌在世代之间完美复制，提供了高度复杂和相同的硅微颗粒的来源。近年来，改变其细胞壁化学性质的能力，无论是通过有机基团的功能化还是通过将金属离子掺入其壳中，都增加了人们对其在催化技术、半导体和生物医学应用中的应用的兴趣。本文综述了硅藻产生壳的基本生物学机制及其在壳制造过程中替代不同金属离子的能力。该综述重点介绍了硅藻壳作为骨组织工程应用中天然衍生生物材料的潜力，以及它们的细胞壁（由生物硅组成）如何部分或完全将其他骨治疗金属离子（例如钛或钙）纳入其壳中。硅藻壳在骨修复中的应用也可能提供一种“更环保”、更环保的生物材料，因为它们可以在相对中性的 pH 值下在环境条件下将硅和其他金属的氧化物自然合成到壳中。这一过程将消除在制造基于硅的生物材料（例如生物活性玻璃）时经常使用的苛刻有机化学品和高温处理条件的使用。
