Long Threads of DNA Sewed into Shape by Machine!

by Rajashri on Jul 13 2008 12:59 PM

A micro-sized sewing machine to sew long threads of DNA into shape has been developed by Japanese researchers.

The work, presented by Kyohei Terao from Kyoto University, and colleagues from The University of Tokyo, shows a unique way to manipulate delicate DNA chains without breaking them.

Scientists can diagnose genetic disorders such as Down’s syndrome by using gene markers, or ’probes’, which bind to only highly similar chains of DNA.

Once bound, the probe’s location can be easily detected by fluorescence, and this gives information about the gene problem.

However, detecting these probes is often a slow and difficult process as the chains become tightly coiled.

The new method uses micron-sized hooks controlled by lasers to catch and straighten a DNA strand with excellent precision and care.

"When a DNA molecule is manipulated and straightened by microhooks and bobbins, the gene location can be determined easily with high-spatial resolution," Terao said.

Researchers use optical tweezers, tightly focused laser beams, to control the Z-shaped micro hook and pick up a single DNA ’thread’.

The hook is barbed like an arrow, so the thread can’t escape.

When caught on the hook, the DNA can be accurately moved around by refocusing the lasers to new positions.

However, just like thread in a sewing machine, a long DNA chain can be unwieldy - so the researchers built micro ’bobbins’ to wind the chain around.

The lasers move one bobbin around another, winding the DNA thread onto a manageable spindle.

Yoshinobu Baba, who researches biologically useful microdevices at Nagoya University, Japan, said that it is ’an excellent idea to fabricate unique microtools that enables us to manipulate a single giant DNA molecule’.

He added that the technology would also be useful for a number of other applications including DNA sequencing and molecular electronics.

The study is published in the Royal Society of Chemistry journal Lab on a Chip.