DNA sewing machine.

Japanese scientists have made a micro-sized sewing machine to sew long threads of DNA into shape. The work published in the Royal Society of Chemistry journal Lab on a Chip demonstrates a unique way to manipulate delicate DNA chains without breaking them (see also Royal Society of Chemistry).

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.

Detecting these probes is often a slow and difficult process, however, as the chains become tightly coiled. The new method presented by Kyohei Terao from Kyoto University, and colleagues from The University of Tokyo, 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," says Terao.

The team used optical tweezers u tightly focused ...