Protein-mediated synthesis of uniform superparamagnetic magnetite nanocrystals
Protein-mediated synthesis of uniform superparamagnetic magnetite nanocrystals
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DOI：
10.1002/adfm.200609448
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发表时间：
2007-04-16
影响因子：
19
通讯作者：
Canfield, Paul C.
中科院分区：
文献类型：
--
作者：
Prozorov, Tanya;Mallapragada, Surya K.;Canfield, Paul C.
磁铁矿纳米晶体是在重组蛋白Mms6的存在下合成的，该蛋白被认为参与细菌磁铁矿磁小体的生物矿化，哺乳动物铁储存蛋白，铁蛋白，以及两种未知的结合铁的蛋白，脂钙蛋白（Lcn2）和牛血清白蛋白（BSA）。为了模拟在趋磁细菌中形成磁铁矿纳米晶体的条件，在聚合凝胶中进行磁铁矿合成，以减缓试剂的扩散速率。重组Mms6促进形成约30个单结构域。均匀的磁铁矿纳米晶体在溶液中，作为验证使用透射电子显微镜分析和磁化测量。在铁蛋白、Lcn2和BSA存在下形成的纳米晶体，不像在Mms6存在下产生的纳米晶体那样具有均匀的大小和形状。与其他蛋白质合成的纳米材料相比，mms6衍生的磁铁矿纳米颗粒在阻断温度以上表现出最大的磁化值，并且磁化率最大。后者表明每个颗粒具有相当大的有效磁矩，这与具有明确晶体结构的磁铁矿的存在一致。电子显微镜分析和磁测量的结合证实了我们的假设，即Mms6促进了均匀超顺磁纳米晶体的形状选择形成。这为合成均匀磁铁矿纳米晶体提供了一条独特的生物启发途径。
Magnetite nanocrystals are synthesized in the presence of a recombinant Mms6 protein thought to be involved in the biomineralization of bacterial magnetite magnetosomes, the mammalian iron-storage protein, ferritin, and two proteins not known to bind iron, lipocalin (Lcn2) and bovine serum albumin (BSA). To mimic the conditions at which magnetite nanocrystals are formed in magnetotactic bacteria, magnetite synthesis is performed in a polymeric gel to slow down the diffusion rates of the reagents. Recombinant Mms6 facilitates formation of ca. 30 run single-domain,. uniform magnetite nanocrystals in solution, as verified by using transmission electron microscopy analysis and magnetization measurements. The nanocrystals formed in the presence of ferritin, Lcn2, and BSA, do not exhibit the uniform sizes and shapes observed for those produced in the presence of Mms6. Mms6-derived magnetite nanoparticles show the largest magnetization values above the blocking temperature, as well as the largest magnetic susceptibility compared to those of the nanomaterials synthesized with other proteins. The latter is indicative of a substantial effective magnetic moment per particle, which is consistent with the presence of magnetite with a well-defined crystalline structure. The combination of electron microscopy analysis and magnetic measurements confirms our hypothesis that Mms6 promotes the shape-selective formation of uniform superparamagnetic nanocrystals. This provides a unique bioinspired route for synthesis of uniform magnetite nanocrystals.