Ostrov Nili, Fichman Galit, Adler-Abramovich Lihi, Gazit Ehud
J Nanosci Nanotechnol. 2015 Jan;15(1):556-61. doi: 10.1166/jnn.2015.9203.
Supramolecular protein assemblies can serve as templates for the fabrication of inorganic nanowires due to their morphological reproducibility and innate proclivity to form well-ordered structures. Amongst the variety of naturally occurring nano-scale assemblies, cytoskeletal fibers from diverse biological sources represent a unique family of scaffolds for biomimetics as they efficiently self-assemble in vitro in a controllable manner to form stable filaments. Here, we harness the bacterial FtsZ filament system as a scaffold for protein-based metal nanowires, and further demonstrate the control of wire alignment with the use of an external magnetic field. Due to the ease at which the bacterial FtsZ is overexpressed and purified, as well as the extensive studies of its ultrastructural properties and physiological significance, FtsZ filaments are an ideal substrate for large-scale production and chemical manipulation. Using a biologically compatible electroless metal deposition technique initiated by adsorption of platinum as a surface catalyst, we demonstrate the coating of assembled FtsZ filaments with iron, nickel, gold, and copper to fabricate continuous nanowires with diameters ranging from 10-50 nm. Organic-inorganic hybrid wires were analyzed using high-resolution field-emission-gun transmission and scanning electron microscopy, and confirmed by energy-dispersive elemental analysis. We also achieved alignment of ferrofluid-coated FtsZ filaments using an external magnetic field. Overall, we provide evidence for the robustness of the FtsZ filament system as a molecular scaffold, and offer an efficient, biocompatible procedure for facile bottom-up assembly of metallic wires on biological templates. We believe that bottom-up fabrication methods as reported herein significantly contribute to the expanding toolkit available for the incorporation of biological materials in nano-scale devices for electronic and electromechanical applications.
超分子蛋白质组装体由于其形态的可重复性以及形成有序结构的内在倾向，可作为无机纳米线制造的模板。在各种天然存在的纳米级组装体中，来自不同生物来源的细胞骨架纤维代表了一类独特的仿生支架，因为它们能够在体外以可控方式高效自组装形成稳定的细丝。在这里，我们利用细菌FtsZ细丝系统作为基于蛋白质的金属纳米线的支架，并进一步展示了利用外部磁场对线排列的控制。由于细菌FtsZ易于过量表达和纯化，以及对其超微结构特性和生理意义的广泛研究，FtsZ细丝是大规模生产和化学操作的理想底物。使用由铂吸附引发的生物相容性化学镀金属沉积技术作为表面催化剂，我们展示了用铁、镍、金和铜对组装好的FtsZ细丝进行涂层，以制造直径范围为10 - 50nm的连续纳米线。使用高分辨率场发射枪透射和扫描电子显微镜对有机 - 无机混合线进行了分析，并通过能量色散元素分析进行了确认。我们还利用外部磁场实现了铁磁流体涂层FtsZ细丝的排列。总体而言，我们提供了证据证明FtsZ细丝系统作为分子支架的稳健性，并提供了一种高效、生物相容的方法，用于在生物模板上轻松地自下而上组装金属线。我们相信，本文报道的自下而上制造方法对扩展可用于将生物材料纳入用于电子和机电应用的纳米级器件的工具集做出了重大贡献。
