Spin and stretch

The electrospinning technique commonly used to produce fibrous materials has now been applied to stretch DNA molecules

Credit: © 2006 ACS

To better understand the mechanical properties of DNA, many techniques have been used to stretch it. However, current methods only stretch a few molecules at a time and often fail to keep the DNA elongated. Now, researchers at Cornell University in the USA have overcome this problem by using a fluid jet to straighten and fix DNA molecules in a protective polymer coating.

Electrospinning is a common technique for making micro- and nanofibres from a variety of materials. The process uses an electric field to extract fluids through a sharp conducting tip. Leon Bellan and co-workers¹ electrospun a cocktail of polyethylene oxide and L-aspartic acid — an organic compound added to prevent DNA from collapsing into bundles — with DNA labelled with a fluorescent dye. When viewed under a fluorescence microscope, the resulting nanofibres displayed discrete fluorescent lines corresponding to DNA strands. An advantage of this technique is that DNA molecules embedded within the nanofibres can be mechanically manipulated without any fragments moving out of their original sequence.

These results offer some insight into the behaviour of electrospinning jets and suggest new possibilities for the sequencing of DNA and the study of its mechanical properties.