Uto Koichiro, Yamamoto Kazuya, Kishimoto Naoko, Muraoka Masahiro, Aoyagi Takao, Yamashita Ichiro
J Nanosci Nanotechnol. 2014 Apr;14(4):3193-201. doi: 10.1166/jnn.2014.8575.
(Apo)ferritins are cage-shaped proteins which have recently received a great deal of attention because the inner cavity of the protein shell can be used as a size-restricted reaction field for the synthesis of nanomaterials. The biomineralization behavior and inorganic nanoparticle (NP) synthesis mechanism of (apo)ferritin in solution systems have been studied but the mineralization behavior of (apo)ferritin on the substrates has not yet been well studied. Here, we conducted quantitative and kinetic analyses of the mineralization behavior of immobilized (apo)ferritin on a polyelectrolyte multilayer (PEM) using quartz crystal microbalance (QCM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) techniques. We demonstrated that the (apo)ferritin immobilized on a substrate synthesizes a ferrihydrite core within the confines of the protein cage; similar to a solution dispersed system. In addition, we applied a ferritin/apoferritin blended monolayer to the study of iron mineralization and revealed that biomineralization in this system is spatially selective. It is important to understand the mineralization mechanisms for the synthesis of other functional NPs as this approach has potential for a broad range of magnetic, catalytic, and biomedical sensing applications.
（脱铁）铁蛋白是笼状蛋白质，最近受到了广泛关注，因为蛋白质外壳的内腔可作为纳米材料合成的尺寸受限反应场。已对溶液体系中（脱铁）铁蛋白的生物矿化行为和无机纳米颗粒（NP）合成机制进行了研究，但（脱铁）铁蛋白在底物上的矿化行为尚未得到充分研究。在此，我们使用石英晶体微天平（QCM）、扫描电子显微镜（SEM）和X射线光电子能谱（XPS）技术，对固定在聚电解质多层膜（PEM）上的（脱铁）铁蛋白的矿化行为进行了定量和动力学分析。我们证明，固定在底物上的（脱铁）铁蛋白在蛋白质笼的范围内合成了水铁矿核心；类似于溶液分散体系。此外，我们将铁蛋白/脱铁铁蛋白混合单层应用于铁矿化研究，并揭示该体系中的生物矿化具有空间选择性。了解矿化机制对于合成其他功能性NP很重要，因为这种方法在广泛的磁性、催化和生物医学传感应用中具有潜力。
