Shaping Magnetite with Poly-L-arginine and pH: From Small Single Crystals to Large Mesocrystals
Shaping Magnetite with Poly-L-arginine and pH: From Small Single Crystals to Large Mesocrystals
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DOI：
10.1021/acs.jpclett.9b01771
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发表时间：
2019-09-19
影响因子：
5.7
通讯作者：
Faivre, Damien
中科院分区：
文献类型：
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作者：
Kuhrts, Lucas;Macias-Sanchez, Elena;Faivre, Damien
控制粒度、粒度分布和胶体稳定性是制备功能纳米材料的中心目标。最近，仿生方法已成功地用于增强对这些材料的合成中的性质的控制。趋磁细菌产生蛋白质稳定的磁铁矿远离其热力学平衡结构。模仿细菌的蛋白质，使用聚精氨酸，我们表明，通过简单地增加pH值，磁铁矿的尺寸增加和单介晶转化诱导。使用同步辐射X射线衍射和透射电子显微镜，我们表明，磁铁矿纳米粒子具有窄的尺寸分布和平均直径为10 +/-2 nm的pH 9，20 +/- 2 nm的pH 10，和高达40 +/- 4 nm的pH 11可以合成。因此，我们选择性地产生超顺磁性和稳定的单域颗粒，仅仅通过控制pH值。值得注意的是，而pH值的增加带来了磁性驱动的尺寸减少磁铁矿没有添加剂，这种依赖于pH值是颠倒的，当聚-L-精氨酸存在。
Control over particle size, size distribution, and colloidal stability are central aims in producing functional nanomaterials. Recently, biomimetic approaches have been successfully used to enhance control over properties in the synthesis of those materials. Magnetotactic bacteria produce protein-stabilized magnetite away from its thermodynamic equilibrium structure. Mimicking the bacteria's proteins using poly-Larginine we show that by simply increasing the pH, the dimensions of magnetite increase and a single- to mesocrystal transformation is induced. Using synchrotron X-ray diffraction and transmission electron microscopy, we show that magnetite nanoparticles with narrow size distributions and average diameters of 10 +/- 2 nm for pH 9, 20 +/- 2 nm for pH 10, and up to 40 +/- 4 nm for pH 11 can be synthesized. We thus selectively produce superparamagnetic and stable single-domain particles merely by controlling the pH. Remarkably, while an increase in pH brings about a thermodynamically driven decrease in size for magnetite without additives, this dependency on pH is inverted when poly-L-arginine is present.