Conductive Metal Nanowires Templated by the Nucleoprotein Filaments, Complex of DNA and RecA Protein

Abstract

Development of preprogrammable conductive nanowires is a requisite for the future fabrication of nanoscale electronics based on molecular assembly. Here, we report the synthesis of conductive metal nanowires from nucleoprotein filaments, complexes of single- or double-stranded DNA and RecA protein. A genetically engineered RecA derivative possessing a reactive and surface accessible cysteine residue was reacted with functionalized gold particles, resulting in nucleoprotein filaments with gold particles attached. The template-based gold particles were enlarged by chemical deposition to form uniformly metallized nanowires. The programming information can be encoded in DNA sequences so that an intricate electrical circuit can be constructed through self-assembly of each component. As the RecA filament has higher degree of stiffness than double-stranded DNA, it provides a robust scaffold that allows us to fabricate more reliable and well-organized electrical circuitry at the nanoscale. Furthermore, the function of homologous pairing provides sequence-specific junction formation as well as sequence-specific patterning metallization.

Synthesis, Manipulation and Conductivity of Supramolecular Polymer Nanowires

“…[1] Biopolymers, and DNA in particular, are well suited to building systems and architectures spanning the nm-mm length scale; [2,3] however, the intrinsically low conductance of this material [4] necessitates further functionalisation for electronic applications. This can be overcome by templating [5] and the deposition of metals such as Cu, [6,7] Ag, [8,9] Au [10,11] and Pd [12] or MoGe alloy, [13] single-wall carbon nanotubes [14,15] and nanoparticles, [16] have been demonstrated as methods for preparing conducting nanowire systems.…”

Visualization of RecA Filaments and DNA by Fluorescence Microscopy

“…The narrower distribution suggests the regularity of the binding stoichiometry and/or binding preference and the shorter values of the filament length suggests that the ATP/dATP hydrolysis expands the region of filament formation on ssDNA by changing the binding stoichiometry and/or unfolding of the ssDNA structure. Direct Fluorescent Labelling of RecA Filaments-In order to directly label the RecA filament with fluorescent reagents, we prepared a cysteine derivative protein, which had one additional cysteine residue at the C terminus of the RecA protein (353C RecA protein) (26). However, the RecA protein has three other cysteine residues in its protein sequence, and the labelling reaction may occur at these residues.…”

“…The 353C RecA derivative, in which one cysteine residue was introduced to the C-terminus of a wild-type RecA protein, was prepared and purified according to the method described before (26), and further purified by anion exchange column chromatography (DE52, Whatman). Escherichia coli strain MV1184 was transformed by plasmid carrying wild-type recA gene or 353C recA gene.…”

Carbon nanotube template-assisted synthesis of zinc ferrite nanochains

“…The nanochain, a typical 1D assembly of nanoparticles, is a new member of the nanostructure family [20][21][22]. Generally, the preparation methods of nanochains can be classified into two main strategies: self-assembly [23][24][25][26][27][28][29][30] and the template-assisted approach [31][32][33][34]. Generally, self-assembly requires more rigorous conditions; for the template-assisted approach, it is difficult to completely remove the template (such as an AAO template) and to control the diameter of products smaller than 100 nm.…”