DuPont, MIT and University of Illinois scientists have discovered an innovative way to advance electronics applications through the use of DNA that sorts carbon nanotubes.

Carbon nanotubes possess excellent electrical properties that make them potential building blocks in a broad range of nanotechnology-related electronic applications, including highly sensitive medical diagnostic devices and transistors more than 100 times tinier than those found in today’s microchips. When they are fabricated, however, carbon nanotubes of different electronic types randomly clump together, deterring consistent conductivity. The ability to sort and assemble carbon nanotubes allows for uniform conductivity, enabling the applications to be realized, according to DuPont.

Initially, the researchers found that single-stranded DNA strongly interacts with carbon nanotubes to form a stable DNA-carbon nanotube hybrid that effectively disperses carbon nanotubes in an aqueous solution. As a follow-up, they discovered a new method for separating carbon nanotubes using single-stranded DNA and anion-exchange chromatography.

By screening a library of oligonucleotides, the team found that a particular sequence of single stranded DNA self-assembles into a helical structure around individual carbon nanotubes. Since carbon nanotube-DNA hybrids have different electrostatic properties that depend on the nanotubes’ diameter and electronic properties, they can be separated and sorted using anion exchange chromatography.

The technique can be used to separate metallic carbon nanotubes from semiconducting carbon nanotubes and sort semiconducting carbon nanotubes by diameters, an important element in nanoelectronic applications.

This research appears in the current issue of the journal Science.

DuPont press release