DNA-templated nanowires: morphology and electrical conductivity

Abstract

DNA-templating has been used to create nanowires from metals, compound semiconductors and conductive polymers. The mechanism of growth involves nucleation at binding sites on the DNA followed by growth of spherical particles and then, under favourable conditions, a slow transformation to a smooth nanowire. The final transformation is favoured by restricting the amount of templated material per unit length of template and occurs most readily for materials of low surface tension. Electrical measurements on DNA-templated nanowires can be facilitated using three techniques: (i) standard current-voltage measurements with contact electrodes embedded in a dielectric so that there is a minimal step height at the dielectric/electrode boundary across which nanowires may be aligned by molecular combing, (ii) the use of a dried droplet technique and conductive AFM to determine contact resistance by moving the tip along the length of an individual nanowire and (iii) non-contact assessment of conductivity by scanned conductance microscopy on Si/SiO2 substrates.

A Nonconventional Approach to Patterned Nanoarrays of DNA Strands for Template‐Assisted Assembly of Polyfluorene Nanowires

“…In order to engineer these self‐organized DNA structures for their integration into electronic devices, the surface modification is essential due to the poor electrical characteristics of DNA. To this end, a cationic conjugated polyelectrolyte (CPE), poly[9,9‐bis(6′‐ N,N,N ‐trimethylammoniumhexyl)fluorene dibromide] (PF2) was used to form a complex with DNA in aqueous solution . The complexation of cationic PF2 with anionic biological polyelectrolytes (i.e., salmon sperm DNA) offers an effective means of building the patterned structures of semiconducting conjugated polymers.…”

Synthetic Biological Protein Nanowires with High Conductivity

“…For example, a single DNA molecule functioning as a conductive wire has the advantage of narrow diameter (2 nm) with lengths of hundreds of nanometers. However, there are large differences in the reported conductivity of DNA nanowires, and the primary application of DNA may be as a template for the patterning of metals or semi‐conductive materials . Biologically produced protein fibers such as silk, actin, collagen, and amyloid fibers are also good templates for metal deposition to produce nanowires, but are otherwise poorly conductive .…”

Spontaneous formation of aligned DNA nanowires by capillarity-induced skin folding

“…DNA nanowires | capillary forces | wrinkling | folding | instability A ssembling biomolecules and microorganisms (e.g., virus and DNA) into a desired architecture has offered new routes to the fabrication of nanomaterials (1,2). In particular, DNA nanowires have proven useful as a template to fabricate functional nanomaterials and as a platform for genetic analysis (3)(4)(5). Molecular combing and its derivatives have been used widely to obtain such nanowires using an aqueous solution of DNA molecules, where capillary forces of the solution at a receding meniscus act to stretch and immobilize the molecules on a solid surface (6).…”