Plascencia-Villa Germán, Saniger José M, Ascencio Jorge A, Palomares Laura A, Ramírez Octavio T
Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, CP 62250, Cuernavaca, Morelos, México.
Biotechnol Bioeng. 2009 Dec 1;104(5):871-81. doi: 10.1002/bit.22497.
The structural characteristics and predefined constant size and shape of viral assemblies make them useful tools for nanobiotechnology, in particular as scaffolds for constructing highly organized novel nanomaterials. In this work it is shown for the first time that nanotubes formed by recombinant rotavirus VP6 protein can be used as scaffolds for the synthesis of hybrid nanocomposites. Rotavirus VP6 was produced by the insect cell-baculovirus expression vector system. Nanotubes of several micrometers in length and various diameters in the nanometer range were functionalized with Ag, Au, Pt, and Pd through strong (sodium borohydride) or mild (sodium citrate) chemical reduction. The nanocomposites obtained were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM) with energy dispersive spectroscopy (EDS), dynamic light scattering, and their characteristic plasmon resonance. The outer surface of VP6 nanotubes had intrinsic affinity to metal deposition that allowed in situ synthesis of nanoparticles. Furthermore, the use of preassembled recombinant protein structures resulted in highly ordered integrated materials. It was possible to obtain different extents and characteristics of the metal coverage by manipulating the reaction conditions. TEM revealed either a continuous coverage with an electrodense thin film when using sodium citrate as reductant or a discrete coverage with well-dispersed metal nanoparticles of diameters between 2 and 9 nm when using sodium borohydride and short reaction times. At long reaction times and using sodium borohydride, the metal nanoparticles coalesced and resulted in a thick metal layer. HRTEM-EDS confirmed the identity of the metal nanoparticles. Compared to other non-recombinant viral scaffolds used until now, the recombinant VP6 nanotubes employed here have important advantages, including a longer axial dimension, a dynamic multifunctional hollow structure, and the possibility of producing them massively by a safe and efficient bioprocess. Such characteristics confer important potential applications in nanotechnology to the novel nanobiomaterials produced here.
病毒组装体的结构特征以及预先确定的恒定尺寸和形状使其成为纳米生物技术的有用工具，特别是作为构建高度有序新型纳米材料的支架。在这项工作中，首次表明由重组轮状病毒VP6蛋白形成的纳米管可作为合成杂化纳米复合材料的支架。轮状病毒VP6由昆虫细胞 - 杆状病毒表达载体系统产生。通过强（硼氢化钠）或温和（柠檬酸钠）化学还原，对长度为几微米、直径在纳米范围内的纳米管进行了银、金、铂和钯功能化。通过透射电子显微镜（TEM）、带有能量色散光谱（EDS）的高分辨率TEM（HRTEM）、动态光散射及其特征等离子体共振对所得纳米复合材料进行了表征。VP6纳米管的外表面对金属沉积具有内在亲和力，这使得能够原位合成纳米颗粒。此外，使用预组装的重组蛋白结构产生了高度有序的集成材料。通过操纵反应条件，可以获得不同程度和特征的金属覆盖。TEM显示，当使用柠檬酸钠作为还原剂时，会形成连续的电子致密薄膜覆盖；而当使用硼氢化钠且反应时间较短时，则会形成离散的、直径在2至9纳米之间的分散良好的金属纳米颗粒覆盖。在长反应时间且使用硼氢化钠的情况下，金属纳米颗粒会合并形成厚金属层。HRTEM - EDS证实了金属纳米颗粒的特性。与迄今为止使用的其他非重组病毒支架相比，这里使用的重组VP6纳米管具有重要优势，包括更长的轴向尺寸、动态多功能中空结构以及通过安全高效的生物过程大量生产的可能性。这些特性赋予了此处生产的新型纳米生物材料在纳米技术中的重要潜在应用价值。
