In new research published in Nature Communications, McGill University chemistry professor Hanadi Sleiman and her team at McGill say that they have devised a new technique to create much longer strands of DNA with custom-designed sequence patterns. What’s more, this new approach also produces large amounts of these longer strands in just a few hours, making the process potentially more economical and commercially viable than existing techniques.
The new method involves piecing together small strands one after the other, so that they attach into a longer DNA strand with the help of an enzyme known as ligase. A second enzyme, polymerase, is then used to generate many copies of the long DNA strand, yielding larger volumes of the material. The polymerase process has the added advantage of correcting any errors that may have been introduced into the sequence, amplifying only the correctly sequenced, full length product.
The team used these strands as a scaffold to make DNA nanotubes, demonstrating that the technique allows the length and functions of the tubes to be precisely programmed.
“In the end, what we get is a long, synthetic DNA strand with exactly the sequence of bases that we want, and with exactly as many repeat units as we want,” explains Sleiman, who co-authored the study with Graham Hamblin, who recently completed his doctorate, and PhD student Janane Rahbani. “This work opens the door toward a new design strategy in DNA nanotechnology,” Sleiman says. “This could provide access to designer DNA materials that are economical and can compete with cheaper, but less versatile technologies. In the future, uses could range from customized gene and protein synthesis, to applications in nanoelectronics, nano-optics, and medicine, including diagnosis and therapy.”
Funding for the research was provided by the Natural Sciences and Engineering Research Council of Canada, the Fonds de recherché du Québec – Nature et technologies, the Canada Foundation for Innovation, the Canadian Institutes of Health Research, and the Centre for Self-Assembled Chemical Structures.