'Mass-production of DNA and RNA in industry' is the future offered by researchers at Kyushu University, Fukuoka, Japan, who are using modified DNA molecules to catch and contain specific sequences of DNA.  The DNA molecules in this pure form can be used to identify genetic problems that cause disease and in the future could be used as drugs.

Single-stranded DNA continually searches for a matching strand to pair up with, in a process known as hybridisation. A DNA strand can only hybridise properly with another strand that is its perfect partner. To find and separate specific DNA sequences Tatsuo Maruyama and colleagues attached the DNA partner of a specific DNA sequence to a hydrophobic tail. This formed what the researchers called a DNA-surfactant.

Surfactants have distinct hydrophilic and hydrophobic sections. When surfactants are extracted into oil they form clusters called reverse micelles, which are spherical structures that hide their hydrophilic heads in the centre of a hydrophobic shell.

The Japanese researchers found that DNA molecules that hybridised with the DNA-surfactant became part of the hydrophilic core of reverse micelles and so could be extracted into oil. DNA molecules that were not perfect partners to the DNA-surfactant weren't hybridised and were left behind, along with any other hydrophilic biomolecules that might otherwise have contaminated the DNA.

Paschalis Alexandridis, a surfactant expert at the State University of New York at Buffalo said, 'I am very pleased to see the recognition capabilities of DNA being applied to the practical - and scaleable - setting of reverse micellar extraction.'  

Maruyama's team say the potential for mass production of high purity DNA is 'of great importance'. The team foresees that their procedure will help reduce the cost of these highly-specific DNA molecules, which are expected to find use as analytical tools and drugs in the near future.

Wendy Crocker