Some Purdue University researchers have developed a silicon-based device that can anchor strands of DNA in nanopores for use in DNA testing.

WEST LAFAYETTE, Ind. - Researchers at Purdue's Birck Nanotechnology Center have shown how "nanopore channels" can be used to rapidly and precisely detect specific sequences of DNA as a potential tool for genomic applications in medicine, environmental monitoring and homeland security.

The tiny channels, which are 10 to 20 nanometers in diameter and a few hundred nanometers long, were created in silicon and then a single strand of DNA was attached inside each channel.

Other researchers have created such channels in the past, but the Purdue group is the first to attach specific strands of DNA inside these silicon-based channels and then use the channels to detect specific DNA molecules contained in a liquid bath, said Rashid Bashir, a professor in the School of Electrical and Computer Engineering and the Weldon School of Biomedical Engineering.

The reuse of computer industry technologies to manipulate and measure biological materials at very small scales promises to accelerate the rate of advance of biotechnology and biological science.

The method makes use of known sequences to detect affinities between anchored and floating strands of DNA.

"When the DNA molecules in the bath are perfectly complementary to those in the channels, then this current pulse is shorter compared to when there is even a single base mismatch," Iqbal said. Being able to detect specific DNA molecules quickly and from small numbers of starting molecules without the need to attach "labels" represents a potential mechanism for a wide variety of DNA detection applications.

Note that this isn't really sequencing where any order of DNA letters can be detected. This approach requires use of strands of DNA that have known sequences. So it won't work well for detecting relatively rare genetic variations (and we each have some rare genetic variations). But nanopore-based DNA sequencers might eventually perform full sequencing of genomes so that all genetic variations existing in one organism can be detected.