Centre for Biomaterials and Biopathways, Zhejiang University, Hangzhou, Zhejiang, China.
Nanoscale. 2010 Nov;2(11):2456-62. doi: 10.1039/c0nr00542h. Epub 2010 Oct 13.
An understanding of controlled formation of biomimetic mesocrystals is of great importance in materials chemistry and engineering. Here we report that organic-inorganic hybrid plates and even mesocrystals can be conveniently synthesized using a one-pot reaction in a mixed system of protein (bovine serum albumin (BSA)), surfactant (sodium bis(2-ethylhexyl) sulfosuccinate (AOT)) and supersaturated calcium phosphate solution. The morphologies of calcium-phosphate-based products are analogous to the general inorganic crystals but they have abnormal and interesting substructures. The hybrids are constructed by the alternate stacking of organic layer (thickness of 1.31 nm) and well-crystallized inorganic mineral layer (thickness of 2.13 nm) at the nanoscale. Their morphologies (spindle, rhomboid and round) and sizes (200 nm-2 μm) can be tuned gradually by changing BSA, AOT and calcium phosphate concentrations. This modulation effect can be explained by a competition between the anisotropic and isotropic assembly of the ultrathin plate-like units. The anisotropic assembly confers mesocrystal characteristics on the hybrids while the round ones are the results of isotropic assembly. However, the basic lamellar organic-inorganic substructure remains unchanged during the hybrid formation, which is a key factor to ensure the self-assembly from molecule to micrometre scale. A morphological ternary diagram of BSA-AOT-calcium phosphate is used to describe this controlled formation process, providing a feasible strategy to prepare the required materials. This study highlights the cooperative effect of macromolecule (frame structure), small biomolecule (binding sites) and mineral phase (main component) on the generation and regulation of biomimetic hybrid mesocrystals.
理解仿生介观晶体的可控形成在材料化学和工程中具有重要意义。在这里，我们报告说，使用蛋白质（牛血清白蛋白（BSA））、表面活性剂（双（2-乙基己基）磺基琥珀酸钠（AOT））和过饱和磷酸钙溶液的混合体系中的一锅反应，可以方便地合成有机-无机混合板，甚至介观晶体。基于磷酸钙的产物的形态类似于一般的无机晶体，但它们具有异常且有趣的亚结构。该混合物是通过有机层（厚度为 1.31nm）和结晶良好的无机矿物层（厚度为 2.13nm）在纳米尺度上的交替堆叠构建而成。它们的形态（纺锤形、菱形和圆形）和尺寸（200nm-2μm）可以通过改变 BSA、AOT 和磷酸钙浓度逐渐进行调节。这种调制效应可以通过超薄板状单元的各向异性和各向同性组装之间的竞争来解释。各向异性组装赋予了混合物介观晶体的特征，而圆形则是各向同性组装的结果。然而，在混合形成过程中，基本的层状有机-无机亚结构保持不变，这是确保从分子到微米尺度自组装的关键因素。BSA-AOT-磷酸钙的形态三元图用于描述这种受控形成过程，为制备所需材料提供了一种可行的策略。该研究强调了大分子（框架结构）、小分子（结合位点）和矿物相（主要成分）对仿生混合介观晶体的产生和调节的协同作用。
